Fuel starvation issues. Help needed!!
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Forum Name: The Boat Shed
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URL: https://www.fishing.net.nz/forum/forum_posts.asp?TID=102093
Printed Date: 30 May 2026 at 5:46am
Topic: Fuel starvation issues. Help needed!!
Posted By: gizzykid
Subject: Fuel starvation issues. Help needed!!
Date Posted: 29 Jun 2014 at 8:20pm
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Hi guys In dire need of some help from some of you gurus. Went out fishing today and had to crawl most the way home due to fuel starvation issues. Really frustrating experience. Symptoms are as follows: Problem occurs at high revs, outboard loses all power. Engine doesn’t die but just loses all revs. After this the outboard seems fine at low revs but once we try to open it up a bit it loses power again. The bulb collapses and takes forever to return to full shape after pumping. Outboard is a 98 Evinrude Oceanpro 115. Underfloor 230L fuel tank. There is a vent on the tank and an in-line water-separation filter. Tried sucking on the vent and it seems to be clear. I’ll give you some history. Bought the boat 3
months or so ago. Originally had a fuel flow gauge fitted. There was a very
minor fuel starvation issue on the test run. The seller said it was a problem
he had experienced before and that it was an airlock in the fuel flow gauge. To
fix it he opened up the fuel line where it connected to the fuel flow gauge and
blew in it. Seemed to work. Talked to the shop who
did the pre-purchase inspection about it and they were pretty certain it would
be the fuel low gauge not being orientated right. Once we got it home we repositioned the gauge and had a number of problem-free trips. Then at a later stage the problem showed up again so we removed the fuel flow gauge. This seemed to work for a while. However, a couple of weeks ago we had the problem rear its head again (flow gauge no longer connected). I opened the fuel line and blew in it (clutching at straws I know) got us through the rest of the trip and the next. Today the problem showed up again big time. Managed to get home by continually pumping the bulb and disconnecting/reconnecting the fuel line at the bulb when it started to collapse. Might also be worth mentioning that we sometimes have problems filling the fuel tank. The gas station pump often won’t stay on and we have to hold the pump handle down in order to get it to fill. The collapsed bulb makes me think it is a fuel line issue rather than an outboard fuel pump issue (but I don’t really know what I’m talking about). Thinking it could possibly be the fuel filter so will replace this ASAP. Anyone have any other bright ideas??????? |
Replies:
Posted By: greghud
Date Posted: 29 Jun 2014 at 8:26pm
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the primer bulb is before or after the filter? if before then the problem is not the filter. can you give it a run on another fuel tank, borrow a tote tank or something? it almost sounds like a blockage in the tanks pickup, that clears for a while when you have stopped to fiddle, it runs ok for a while till you pick it up again..... greg
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Posted By: krow
Date Posted: 29 Jun 2014 at 8:39pm
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A few places to start. As the bulb takes a while to inflate then you have a blockage somewhere before the pump, or in the pump. Most likely cause is blocked or semi blocked tank fitting. You need to check all fittings between the tank and the pump. Including the inlet of the pump. Disconnect the hose off the tank and put it in a petrol tin. Does the pump inflate and deflate better? If the blockage is as severe as it sounds the pump should also get sucked flat when in transit. if it doesn't then replace the whole pump. If you just have a straight hose directly off the tank and blowing down the tube temporarily clears the blockage then you have something blocking the intake inside the tank. This isn't so easy to fix but could be a bit of gasket material or something. Don't worry about the the pump flicking off when filling it's most likely just to be to narrow an inlet pipe or too many bends. If your fuel filter is before the pump check it too. As above just leave the filter inline while testing off another petrol container. Hint it might be easier to disconnect the supply off the motor and pump into another container so fuel flow can be assessed. |
Posted By: Tagit
Date Posted: 29 Jun 2014 at 8:44pm
| Which way are you blowing? Towards the tank or the engine, and is the fuel filter between the place you blow and the engine?First guesses would be strainer on the tank pickup if it has one or maybe ethanol/age damage inside the fuel line. |
Posted By: of2fsh
Date Posted: 29 Jun 2014 at 8:57pm
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Or crud/ plastic in the tank blocking the outlet,this would explain the randomness,when its blocked the pump is sucking the primer bulb flat as it cant get enough fuel. Had this on my wife's BMW car ,very easy fix in the end that had me thinking big $$$, small piece of plastic on tank strainer that must of dropped off when car stopped then picked up at higher revs ------------- 2009 and 2010 BERKLEY SOFTBAIT COMP CHAMPS,Runner up 2013 ( solo),winner 2013/14 longest kingfish nz fishing competition |
Posted By: onboard
Date Posted: 29 Jun 2014 at 9:06pm
| check fuel lines, there could be a bend somewhere, or crushed by salt buildup. |
Posted By: gizzykid
Date Posted: 29 Jun 2014 at 9:08pm
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Hey guys Thanks heaps for the quick replies. At the start of the day before starting the primer bulb inflates fine but after I have the starvation issue the bulb is collapsed and doesnt reinflate. Setup is: Tank - Fuel filter - Primer bulb - Outboard When blowing I have just been disconnecting the fuel line on the bulb (on the tank side) and blowing into both the fuel line and bulb. OK so if I try connecting it: Tote tank - fuel filter - primer bulb - outboard and don't have any issues I can assume the issue is either in the tank fitting or hose between tank and filter. Is this right?? The problem is the issue only seems to occur after a while of travelling and so cant test at home or on a quick trip. Sort of need to be heading out a good distance. Maybe on my next trip I'll take a tote tank and if the problem occurs I'll switch over to the tote and see if its still an issue.
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Posted By: yknot
Date Posted: 29 Jun 2014 at 9:11pm
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Check any connection points, any quick connects with o ring missing/pinched? ------------- Those that say it can't be done are being overtaken by those doing it. |
Posted By: gizzykid
Date Posted: 29 Jun 2014 at 9:15pm
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Might also replace the fuel lines between tank-filter and filter-bulb to be safe. Would replace bulb-outboard line also but am not sure about the outboard side of things. How easy is it to replace the fuel line at the outboard end?? Is it a simple connection as per elsewhere or is it something fancy and complicated? How would I go about checking the tank outlet? Just remove the hose and take a look?? Pretty new to all this. Thanks heaps guys
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Posted By: greghud
Date Posted: 29 Jun 2014 at 9:43pm
i am gonna bet the filter is full of crap. greg
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gizzykid wrote:Posted By: SurTAS
Date Posted: 29 Jun 2014 at 10:14pm
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Had a very similar scenario with our 175 honda. The fuel line was crushed by salt build up at the point of entry to the motor itself. I clean it out every year now. Damn I wasted some time checking this line, that filter, this tank that tote. Simple fix in the end. ------------- Just 1 more.... |
Posted By: Betty Boop
Date Posted: 29 Jun 2014 at 10:19pm
I had this issue and we chased it for months. We asertained that the pickup entry though the tank had porus welding. The problem was solved by smearing sika urethane, all over the weld. We spotted it finally when we replaced the line to tank with clear and found a trail of air bubbles causing it to activate the limp mode, due to starvation .......good luck
------------- Last week I joined an Anti-Social support group........They won't talk to me! Papamoa fi-Glass Viscount |
Posted By: Steps
Date Posted: 30 Jun 2014 at 9:36am
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The problem is the issue only seems to occur after a while of travelling Bulb sucking in The pump must be working to pull the bulb in and no air leaks between the bulb and tank u blow back down into the tank, runs fine.. for a while Any debris that maybe causing the blockage gets blown back out... into the tank. OR and perishing , disinergation of the inner lining of a fuel hose gets blown back out...or flap blown back. A common issue on 'home' repairs, for cars is not using the correct vaccuum type fuel hose From your description it wil be either wrong type or perished hoses, blocking or sucking closed OR crap in the fuel tank... illustrate this, an old dirty trick was to put feathers in a car fuel tank... car runs fine but as the feathers get close to the tank pick up they collect and eventually block... stop and they float away... Replace the fuel filter, regardless of how old....pour the contents out and open it up for inspection Replace all hoses from bulb to tank.. at least.. if they are the wrong spec because of poor previous workmanship, may pay to replace the lot just incase.. and check the filler hose to tank, for spec and inside condition And caustion tunning a engine of that size on a tote take WoT....many totev tanks are designed for small engines and the fittings dont flow enough fuel, and could run lean. Get this sorted very soon... running lean/ running out of gas is very destructive to engines |
Posted By: gizzykid
Date Posted: 30 Jun 2014 at 10:07am
Sweet thanks mate. Shoot didn't realise this was potentially doing significant damage to the outboard. Will get it sorted before I run the outboard again for sure. Will definitely replace fuel filter and all fuel hoses. I'll have a chat to the local marine store and grab the new hose off them to make sure I get the correct hose type. If the issue turns out to be crap in the fuel tank how would I go about cleaning it out?? Assume I would need to empty and remove the tank completely, then flush it out (using petrol). Is there any other way of doing it?? Will also check and possibly replace the filler hose and suppose I may as well do the vent hose while I'm at it. .
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Posted By: Joker
Date Posted: 30 Jun 2014 at 10:30am
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RE If the issue turns out to be crap in the fuel tank how would I go about cleaning it out?? A garden hose used as a syphon with the end in the tank moved all around the bottom would suck the crap out like a vacuum. |
Posted By: Steps
Date Posted: 30 Jun 2014 at 3:26pm
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Pull the tank out.... yeah sounds like a big job.. but once have a few jumble clips undone, couple guys.. MT it, remove the sender unit.. chances are the screws will be stuffed so may have to get the drill or grinder out to remove them.... a good flush with a hose... Drain , a 1/2 L meths, good rinse out .. The meths dissolves any moisture. repeat again.... Throw a couple L premixed 2 stroke in, rinse out.. and if all clear replace the tank And while at it replace all hoses... And dont buy the hoses at a marine place, they charge like a rabid wounded bull on heat. Automotive supplies.... I will make something clear here.. for the last 40yrs I have not been a 'boat' person, more classic/ vintage/ muscle cars.. but the principles are the same |
Posted By: gizzykid
Date Posted: 30 Jun 2014 at 3:56pm
Yeah was thinking I had may as well do the job properly and remove the tank completely. Will be a good opportunity to inspect the hull etc also. Sweet so rinse with water followed by meths followed by petrol. Thanks for the heads up about where to buy fuel line. I'll shoot into supercheap and pick some up. What is the correct spec to be using?? i.e what sort of fuel line should I be asking for?? Don't want to end up putting the wrong hose in. . |
Posted By: gizzykid
Date Posted: 30 Jun 2014 at 4:32pm
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Just had another thought. Prior to the last trip I flooded the hull with fresh water and left it for a couple of days (was meaning to empty it the next day but this didn't happen for some reason or another). I wonder if there is a leaky join or weld somewhere in the fuel tank and some fresh water found its way into the fuel. I have flooded it a couple of times previously also. Could this be causing the issues perhaps??
Although I suppose this doesn't explain why the issues were also occurring before we bought it. Side note: I flooded the hull because the trip before someone had left the bung out of the bilge and we ended up with a whole lot of bloody water and bits of fish etc in the hull. I have also been told that it is good to flood the hull periodically with freshwater to flush out saltwater and help prevent corrosion. Is this a wise idea or am I better off just draining the saltwater and leaving it at that?? . |
Posted By: Don18025
Date Posted: 30 Jun 2014 at 4:47pm
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Gizzy, to clean the tank thoroughly you may have to cut an inspection panel in the top of the tank if it does not have one now. There is no easy method for getting inside a fuel tank and getting everything out of it. If the tank is baffled make the inspection port to cover each side of the baffle. If you had freshwater in the tank you would spot this when you drain your filter regularly. Always drain your filter into a clear container and any water will show up as a bottom layer. Petrol floats on water. Before you re-install the tank, pressure test it to check for leaks, especially round the new inspection panel that will be screwed down on a gasket. My guess is that you have something solid in your tank that is blocking the suction tube. |
Posted By: Steps
Date Posted: 30 Jun 2014 at 5:55pm
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Thanks for the heads up about where to buy fuel line. I'll shoot into supercheap Super cheap IS NOT a Automotive industry supplier, it is where boy racers go to buy elcheapo low quailty chinese BS products... yeah I go there to get my car wash, polish,(And I still buy the expensive Megures stuff,) and they do have Timken wheel bearings... and crap chinese ones to... For the suck side u need quailty Fuel grade vaccuum hose, stainless steel jumble clips.. not the cheap chinese stainless either... chances are your local TRADESMAN automotive work shop will have a supply Even a baffle tank, once u have the sensor port and inlet port open , u can get inside and blast the crap around....If really want to get into it, mix up a cup of dishwash powder in a gal of hot water pour inside, slosh around and leave for 10 mins to 1/2 hr.. then blast the heel out of the inside as best as can If want to check for leaks... good idea.. block off all the ports... fill with water, a LIGHTLY pressurise with a vaccuum cleaner that has a blow.....just enough to see the tank expand a little, this will also open any leaks that may occur between a cold winters day and a hot summers day..Use common sence here |
Posted By: krow
Date Posted: 30 Jun 2014 at 8:13pm
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If the filter has had to stop a lot of water it may well be blocked or partially blocked. Your engine will easily run on a tote. Careful filling the hull with water as it puts a lot of weight on pressure points like the trailer rollers.
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Posted By: Steps
Date Posted: 01 Jul 2014 at 4:04pm
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The back ground to the tote was I intended to buy a tote tank for spare fuel, the engine agents strongly suggested not to , but spare carry tanks and if required fill the main tank... because of lean issue under WOT loads for the size of engine. The tote tanks where quite a bit more expensive which made me think and still do there is something in what they say. Just a thought.. |
Posted By: Big -Dave
Date Posted: 01 Jul 2014 at 7:30pm
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I would look at the hoses first. Repco or super cheap sell 'gates' branded rubber fuel hose, which I have alwys used in my boats for the last 20 years. Realistic lifespan of 7-8 years when not in the sun. Cut the old hoses in half and inspect.. Where in the tank is the filler?, is it at the back next to the pickup? Maybe you could remove the filler and look in there with a torch and see if there is any crap, you may need to tilt the boat to one side. At that point you could siphon the petrol out with a garden hose as suggested up there and suck up any crap. If you have to remove the gauge, and the screws are stuffed, drill the heads off, dont use a grinder, or you will be on the news.. |
Posted By: gizzykid
Date Posted: 01 Jul 2014 at 8:06pm
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Hey guys Made a start on this tonight. Started by replacing the fuel filter. The old filter had a fair amount of crap in it and quite a few bits of rubber. I assume this is from the fuel hose and is probably a good sign that they need replacing. Then opened up the hatch to get access to the fuel tank. Disconnected and blew down the vent hose. Seemed fine. Removed the sender unit - which came off all good, no seized screws - and took a quick look inside the tank but couldnt see much. Still need to find somewhere to store the 100-odd litres of gas still in the tank. Once this is done I'll flush and clean out the tank and check for leaks. Then will replace all the hoses in the system. |
Posted By: of2fsh
Date Posted: 01 Jul 2014 at 8:38pm
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Good that you've found something,new hoses and a tank clean out and she's all good to go,don't forget to replace hose clamps as well if they look suspect ------------- 2009 and 2010 BERKLEY SOFTBAIT COMP CHAMPS,Runner up 2013 ( solo),winner 2013/14 longest kingfish nz fishing competition |
Posted By: Durban
Date Posted: 01 Jul 2014 at 10:04pm
| A point of interest a power pack that fires intermittently on a 4 cylinder gives the same sort of symptoms as fuel starvation the motor ends up bogging down as you throttle up because only 2 cylinders are firing from experience at times it would fire on all 4cylinders and sometimes only on 2 cylinders . once you have changed all the fuel lines etc , & it does it again suspect power pack busy plying up .this is when you need a timing light on board clip it over the HT leads to find out which bank is not firing . |
Posted By: gizzykid
Date Posted: 04 Jul 2014 at 6:24pm
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Hey guys Need some more advice please. Picked up some new 5/16" dia fuel hose from the marine shop today (talked to a mate who works at an automotive workshop and he said they just get their hose from Repco. Repco prices were similar to marine shop). I am a
bit concerned that the new hose is not the right stuff. The existing hose is a thick walled black hose with woven-fibre reinforcing and is quite stiff. The new hose is thinner walled, non-reinforced and is very flexible (it kinks quite easily), its blank without any text on it. Which is
the correct stuff?? What stuff should I be using?? Also do I need to use a different hose for the portion of pipe that is underfloor and the portion that is above deck and exposed to sun/salt etc? In total there is almost 7m of hose between the tank and outboard. This sounds like a lot. Is this perhaps causing problems?? Should I be upsizing to 3/8" hose to try to reduce resistance?? Thanks guys |
Posted By: Tagit
Date Posted: 04 Jul 2014 at 6:50pm
| How can you have 7m of fuel hose on a little boat? Sounds weird. Anyway, from your pretty detailed descriptions, your problem has quite possibly been the old fuel line collapsing (internally) under suction due to aging. Replacing it with a long length of thin walled hose is only asking for that problem to happen again quite quickly. It also sounds potentially risky. Get yourself some decent reinforced hose, and yes if it is 7m of small hose, going up a size probably wouldn't hurt. Did you try borrowing a tote tank and running off that to confirm your problem is the fuel feed? |
Posted By: Durban
Date Posted: 04 Jul 2014 at 7:09pm
| Preferably Neoprene reinforced rubber hoses . |
Posted By: Get in behind
Date Posted: 04 Jul 2014 at 7:56pm
| I think they've sold you vacuum hose. They did it to me once |
Posted By: gizzykid
Date Posted: 04 Jul 2014 at 11:58pm
Yeah I know...I seriously don't know how it adds up to 7m but measured it a couple of times. Hose runs underfloor from tank to transom. Then comes up through floor and loops around through fuel filter. Then goes across transom to the side of the boat where it enters a conduit along with oil, electrics etc and goes through transom. Then runs across duckboard to outboard. I'm gonna try to reduce this length if possible.
Haha yeah get a bit carried away on the keyboard at times.
Sweet will return the new hose and get some reinforced stuff. If nothing else it will put my mind at ease Just realised the fittings on the tank etc are all for 5/16 hose so will probably end up sticking with that size to save some hassle.
Nah haven't yet. Figure the hoses etc need changing anyway so will do this first. Will take a tote out next trip and if the problem is still happening I'll try running it off this and see what happens |
Posted By: gizzykid
Date Posted: 05 Jul 2014 at 6:20pm
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Siphoned out the gas from the tank today so I could get stuck into the work. Removed the tank and opened up the fuel gauge sender and fuel pickup. The fuel pickup was jammed full of scraps of rubber. I'm almost certain this was the cause of my issues. When I had a good look inside the tank it was littered with rubber. I figured this must be coming from the fuel fill pipe so I whipped this off and sure enough the inside was badly deteriorated and peeling off in large chunks. Spent an hour or so with a little flexible pick up tool picking out the chucks of rubber that I couldnt flush out. Pretty tough in a baffled tank with only a very small opening. Got most of the chunks but will have to have another go tomorrow as I ran out of daylight. Stoked to have found the root of the problem though. Thanks for all your help guys. Appreciate it. |
Posted By: Don18025
Date Posted: 05 Jul 2014 at 6:26pm
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Keep at it Gizzy You want that tank to be 100% clean..... The last place you want t be is back of beyond and the wind gets to 30 knots and the motor cannot get enough gas. Thanks for keeping us posted with your results.
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Posted By: smudge
Date Posted: 05 Jul 2014 at 10:40pm
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Well done, I think you've found the problem alright. ------------- Best gurnard fisherman in my street |
Posted By: larsandjo
Date Posted: 06 Jul 2014 at 8:38pm
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these exact symtpoms happened on our new bost also. ran fine.... stopped after about 20 minutes, primer bulb deflated etc etc. ended up replacing primer pump bulb, hose from bulb to intake of tank and few other bits. ended up being ecu, the signal would be intermittent to the fuel pump. expensive fix for us... but goes great now. |
Posted By: Steps
Date Posted: 07 Jul 2014 at 5:08pm
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Glad its sorted New hoses clips , fresh tank... u now head out on a long fish, KNOWING the tank is clean, hoses are new and nothing on the back of the mind....and relax. I would also suggest to replace the O ring around the filler cap to And where possible double stainless jubilee clips , espec on the filler hose... I think it maybe a insurance/survey requirement?? |
Posted By: gizzykid
Date Posted: 21 Jul 2014 at 9:01am
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The weather has been abysmal in my neck of the woods lately but finally got the boat back on the water over the weekend. Took a few attempts and a bit of
spluttering to start the outboard but I assume this was just the outboard
needing to prime itself and burn off a bit of excess oil etc after replacing
the fuel hoses. Once I got it started it ran perfectly. No issues at all even at WOT. Really happy to have the issue sorted and the boat back in action. Thanks for all the advice and info guys. Some top blokes on this site. Just have to sort out the bloody
weather now. |
Posted By: krow
Date Posted: 21 Jul 2014 at 8:12pm
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Top stuff and thanks for the update. Was the replacement inlet pipe expensive? It should have been. Also if possible double clamp it to the tank and check tightness after a few months. This is one place WATER can get into the underfloor, especially if you're going to fill the hull now and again.
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Posted By: gizzykid
Date Posted: 21 Jul 2014 at 10:27pm
Not too sure how much the filler pipe was worth. A mate who works at one of the big boat manufacturers hooked me up with a short length of it. Yep, gave the pipe some good overlap and double clamped everything but will definitely check again in a few months time.
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