Johnson 70hp Issues
Printed From: The Fishing Website
Category: General Forums
Forum Name: The Outboard Clinic
Forum Description: Anything related to outboard maintenance here....
URL: https://www.fishing.net.nz/forum/forum_posts.asp?TID=66279
Printed Date: 07 Nov 2026 at 4:38am
Topic: Johnson 70hp Issues
Posted By: GrizzlyKiwi
Subject: Johnson 70hp Issues
Date Posted: 23 May 2011 at 9:02am
| I had some annoying things happen yesterday out on the water with my 70ESL Johnson... sometimes its a little bit hard to start and sometimes is starts first turn of the key. The other issue was it seemed to have a miss/sluggish at low revs when taking off and a bit of a knock sometimes... once it was up to speed it was absolutely fine. Does anyone have any idea what this could be? |
Replies:
Posted By: paw
Date Posted: 23 May 2011 at 10:43am
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Check the fuel bowl for water?????????????? ------------- sleeping is a symptom of caffeine deprivation |
Posted By: GrizzlyKiwi
Date Posted: 23 May 2011 at 11:38am
| thanks mate i will check that... i thought it might be an electrical issue but i checked the battery and its readying 12.84 volts which is fine and i recently replaced the ignition coils. |
Posted By: Moki Marko
Date Posted: 23 May 2011 at 11:40am
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How old is it? |
Posted By: GrizzlyKiwi
Date Posted: 23 May 2011 at 11:44am
| 1974 its had a full recon and has approx 60 hours on the clock since then |
Posted By: Outboard Performance
Date Posted: 23 May 2011 at 12:32pm
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Why did you replace ignition coils? Outboards should not knock... |
Posted By: GrizzlyKiwi
Date Posted: 23 May 2011 at 12:38pm
| i replaced the coils because they were cracked... as for the knocking it could have just been a miss but main issue was the sluggishness at low revs and the not always starting first turn of the key. |
Posted By: GrizzlyKiwi
Date Posted: 23 May 2011 at 12:55pm
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Also last time i had a compression test all 3 cylinders were at 110 psi |
Posted By: Outboard Performance
Date Posted: 23 May 2011 at 3:07pm
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This might help, if not - let me know
Excuse the poor audio - need a mic
|
Posted By: GrizzlyKiwi
Date Posted: 23 May 2011 at 3:43pm
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I think i might take the boat for a run on the river and take some video and see if i can replicate the problem, it might be easier than trying to explain it. As for the plugs i did get them all replaced a few months ago when i got the motor serviced. |
Posted By: Moki Marko
Date Posted: 23 May 2011 at 4:00pm
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I spent thousands trying to get an old johnson going properly - unsuccessfully, then the next owner spent more money then the crankshaft broke and then he threw it away and thats what I should have done and thats what I advise everyone else with old outboard motors to do |
Posted By: GrizzlyKiwi
Date Posted: 23 May 2011 at 4:27pm
| unfortunatley i cant afford a new motor now |
Posted By: Southern_Jez
Date Posted: 25 May 2011 at 10:09am
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I just got over some intermittent issues with my Johnson 140. Turned out it all came down to a dodgy connection in the main wiring loom plug (big red round plug on my motor). Cleaned that out, and tightened up the female plugs a little and now she runs sweet.
That said, in the process we changed the coils, new starter motor, new power pack, cleaned out the carbs, all with no resolution. Oh the joys of intermittent problems.
|
Posted By: GrizzlyKiwi
Date Posted: 25 May 2011 at 4:11pm
| its weird cause i tried the motor at home last night and started it 6 times in a row first turn of the key... the only thing i did was put in a new 3/8" inch fuel line and new inline fuel filter. Im going to take it for a run on the river and see how it goes. |
Posted By: Moki Marko
Date Posted: 28 May 2011 at 9:36am
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I know I sound like a 'big meany negative guy' but these motors were just not made to last, every single part is well past it's use by date, every wire is brittle, every connection is corroded, every moving part has been stressed and will eventually fail - I know it sounds harsh but if you cant afford a newish motor then you absolutely can't afford an old one. |
Posted By: GrizzlyKiwi
Date Posted: 28 May 2011 at 6:00pm
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it had $1200 spent on a recondition not long before i got it so its not like it has all the original parts... |
Posted By: Outboard Performance
Date Posted: 28 May 2011 at 6:16pm
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$1200 can't be a recondition... Too cheap. Do you have a list of what was done? The motors themselves are a pretty strong engine. It's usually the elctronics and ignition that give problems. Coils, stators, powerpacks etc... |
Posted By: Elevate
Date Posted: 28 May 2011 at 6:34pm
| 1200 is pretty cheap for a recondition we had a 50 Johnson done and that set us back about 3000 maybe even a little more. Hopefully you can get it sorted out !! |
Posted By: Moki Marko
Date Posted: 28 May 2011 at 7:09pm
| as I said, I don't want to be the wet blanket, so I'm just keeping the conversation going, I think the fact that it's had $1200 spent on it and it still doesn't go properly kinda proves my point - maybe? |
Posted By: GrizzlyKiwi
Date Posted: 28 May 2011 at 10:24pm
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the work he had done on it was as follows Motor has had new bearings, gaskets, seals, pistons and rings, Leg was reconditioned approximately 2 years ago, Water impeller and gear box oil checked only 2 months ago so it wasnt a full recon but did have a fair bit done to it. |
Posted By: GrizzlyKiwi
Date Posted: 28 May 2011 at 10:25pm
well im not sure about it not working as i would expect... i will need to test it out again on the water.
|
Moki Marko wrote:Posted By: GrizzlyKiwi
Date Posted: 29 May 2011 at 7:43pm
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took some video tonight and didnt have the same problems as the other day... i did have an issue where at high revs it surges? is it a miss? |
Posted By: Double Shot
Date Posted: 29 May 2011 at 8:09pm
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May seem like a silly question, but was the breather open on the fuel tank? ------------- 70ml of 90deg C water pressurised through 13g of roasted finely ground tamped coffee for 25sec's to make a distinguishing sensory hit called a Double Shot |
Posted By: GrizzlyKiwi
Date Posted: 29 May 2011 at 8:11pm
yeah it was mate that was the first thing i checked :)
|
Posted By: RC1
Date Posted: 29 May 2011 at 8:17pm
| sounds like a fuel starvation problem, was the fuel pump and fuel line assembly replaced when the engine was reconditioned. I would recommend these items to be replaced after an engine recondition. |
Posted By: GrizzlyKiwi
Date Posted: 29 May 2011 at 8:52pm
| I just replaced the fuel line and fuel filter but im not sure if the pump was replaced when it had a recondition. |
Posted By: RC1
Date Posted: 29 May 2011 at 8:54pm
| ok, just make sure you use a genuine or good quality fuel line and proper fuel clamps, dont use one of those fuel line assys from Burnsco, they are good for the rubbish bin. |
Posted By: GrizzlyKiwi
Date Posted: 29 May 2011 at 8:59pm
| funny you should say that i bought a new fuel line (grey OMC one) from Burnsco and thats whats on there atm... its one of http://www.burnsco.co.nz/Products_28.aspx?CategoryId=217&ProductId=17585 - these |
Posted By: GrizzlyKiwi
Date Posted: 01 Jun 2011 at 10:11am
Did a compression test last night and checked the spark from the coils and it all showed up good! especially the compression which was 150psi on all 3 cylinders!! i had to do it twice to make sure  |
Posted By: Outboard Performance
Date Posted: 01 Jun 2011 at 12:44pm
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You can do two things to check if its fuel system when doing it... a, you can push the key in to choke the motor and see if it takes off... If you hold it in too long you will flood it. So give it short pumps b, prime the fuel primer to see if the fuel pump isn't working properly. Have you taken the little plastic inlet off the fuel pump and checked inder the gauze/filter for signs of debris? If there is crap under that 99% you will need to remove and strip your carbs. |
Posted By: GrizzlyKiwi
Date Posted: 01 Jun 2011 at 2:32pm
Im going to check the fuel pump gauze tonight... i did order a fuel pump kit for $32 and am going to check out the carbs with a mate on the weekend. |
Posted By: GrizzlyKiwi
Date Posted: 02 Jun 2011 at 4:56pm
| well i checked the fuel pump and it was nice and clean... the gauze was like new. |
Posted By: Outboard Performance
Date Posted: 02 Jun 2011 at 5:32pm
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Might be time for the shop mate.... Also make sure your warning horn works... Turn your ignition key on, and the tan wire that comes out of the head, pull the insulation sleeve back from the connector and earth it against the head, the warning horn should sound... |
Posted By: Clutch
Date Posted: 02 Jun 2011 at 5:53pm
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Posted By: GrizzlyKiwi
Date Posted: 03 Jun 2011 at 8:53am
yeah im thinking the same mate... i will check the horn and see if it goes. |
Posted By: Durban
Date Posted: 18 Sep 2012 at 12:24pm
| if you haven't got it sorted yet make contact with me i will fix it for you free . cheers |
Posted By: GrizzlyKiwi
Date Posted: 18 Sep 2012 at 12:39pm
| thanks Durban but ive got a new 90hp Yamaha now mate |
Posted By: JEFFRO
Date Posted: 30 Oct 2012 at 6:04pm
| http://www.fishing.net.nz/asp_forums/forum_posts.asp?TID=84203&title=fuel |