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Suzuki 90hp vibration/noise

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=137418
Printed Date: 26 Feb 2026 at 10:05am


Topic: Suzuki 90hp vibration/noise
Posted By: bricker
Subject: Suzuki 90hp vibration/noise
Date Posted: 15 Jan 2023 at 10:34pm
Hi folks

Seeking a little advice in regards to outboard performance. Recently purchased a secondhand Surtees 5.5 Workmate c/w Suzuki 90HP outboard (400 hours with complete regular service history).
Having had ETECs, an Optimax and recently a Yamaha 90hp 4 stroke, I was looking forward to getting the boat wet today after the recent atrocious weather.
Boat is awesome and just what I was hoping for. The outboard wasn't !!! It was quiet enough at idle but push the throttle forwards and there's a vibration that doesn't want to go away at varying engine revs. The noise was also a huge disappointment.........it's as though the outboard is right next to you and it's actually quieter standing right next to the outboard compared to standing at the helm. A short 20 minute run at varying speeds/tilt settings etc. was all we could take before my son and I both had headaches ......there's no way you can hear someone next to you.
To be honest I'm absolutely gutted and actually considering taking the boat back to the vendor (it was a private sale) and asking for a refund.......but before I show my ignorance, maybe someone can point out some basic tests/checks I could do to see if there's any improvement?
Thanks in advance



Replies:
Posted By: RogueOne
Date Posted: 16 Jan 2023 at 12:44pm
The vibration is not there in neutral but only when the motor is in gear?
Could be unbalanced propeller or something in the gear case? Can you try a loaner propeller from somewhere?

Loose engine mount? I assume you've taken the cover off and looked at the motor to see if there is anything obvious touching a moving part?  


Posted By: smudge
Date Posted: 16 Jan 2023 at 2:21pm
As Rogue One said. A damaged prop would be the first thing I would look at, along with the engine mounts. It may also be an inherent problem with those motors. I know the Suzuki 140 had an issue on tinny hard tops with a resonance causing a problem similar to what you're describing.

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Best gurnard fisherman in my street


Posted By: smudge
Date Posted: 16 Jan 2023 at 2:26pm
Here's an older link to a very similar problem:  https://www.fishing.net.nz/forum/vibration-issues_topic94825.html%20" rel="nofollow - https://www.fishing.net.nz/forum/vibration-issues_topic94825.html

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Best gurnard fisherman in my street


Posted By: bricker
Date Posted: 16 Jan 2023 at 10:42pm
Thanks for the input folks.
Rant over, I have tried to put some logic and rationale into the issue!!
Firstly.....there is a spare prop so will try that. A work colleague suggested contacting Surtees for some advice as he had heard they are very helpful with tips on setting up boats for those that purchased a second-hand Surtees.
Interestingly, I had a closer look at the outboard configuration/mounting. I have always been told that the cavitation plate should be approximately level with the bottom of the hull. Well....on mine, the plate is about 7.5cm above the lowest point of the hull. (picture below shows distance between the two with top leading edge of timber level cavitation plate - a distance of 7.5cm.

Furthermore, there is also an alloy wedge that has bee inserted between outboard and mounting plate on hull. I'm not sure what purpose this serves, but that is where I would expect to find a rubber pad to dampen any vibration from the motor. Picture below illustrates this.


Any thoughts Gentlemen??










  


Posted By: smudge
Date Posted: 17 Jan 2023 at 6:19am
I've no experience at setting up motors but that one looks a little too high. Does it cavitate? You would notice that particularly on turns. My understanding is that wedges are there to optimise trim settings. The mounting bolts would need washers the same profile as the wedge or they would be under some high radial loads. Be interesting to see what Surtees say.

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Best gurnard fisherman in my street


Posted By: Snuffit.
Date Posted: 17 Jan 2023 at 12:23pm
I'm running a DF90 on my Haines Signature 485sf. I have the benefit of a jack plate for shallow water running so have a fair idea what happens when the motor is set too high - cavitation and vibration galore (even though I get to zap along on plane in <40cm of water.... when i have the balls to, not often). When I drop the plate right down at full noise performance is less than optimal (no vibration though) so there's probably something in the way yours is set up. I can hold a conversation without too many issues at 20 odd knots, being an open boat wind noise is louder for me. 

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You cant eat my toast fish


Posted By: krow
Date Posted: 17 Jan 2023 at 9:00pm
I can comment on the wedge plate. It's there for trim improvement. I had to have one installed for my Suzuki 140 as it would not trim High enough on my pod. Mine is not as thick as yours but does the job. Without it I was running at 100% trim and felt I couldn't get the max trim for planning. Now run around 95% trim as ideal speed v ride v economy. I also recon it should be quieter as mine is quieter than the Merc I replaced it with and my previews boat with the Suzuki 70 was also quiet. 


Posted By: krow
Date Posted: 17 Jan 2023 at 9:01pm
Oh the vibration try running it on muffs and put it into gear. Cover off. Just a thought.


Posted By: bricker
Date Posted: 19 Jan 2023 at 7:43am
Thanks for the advice.
Surtees have been very helpful with info on the boat and their take on it…….thank you Mark!!
They do recommend an anti-vibration pad between hull and outboard, and also feel the outboard is a couple of inches high. I’ll adjust this weekend and see if that cures the issue.


Posted By: smudge
Date Posted: 19 Jan 2023 at 7:18pm
That's good news Bricker. Did they mention anything about the need for those wedges and the subsequent angle of the mounting bolts? It certainly looks a bit too high to me

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Best gurnard fisherman in my street


Posted By: bricker
Date Posted: 22 Jan 2023 at 2:56pm
Update:
Fitted Vibropad between outboard & transom.........less vibration but still there when cruising (I checked and motor itself is all good and everything is as it should be).
Lowered outboard by 40mm on transom. Noise levels are reasonable when standing right next to motor but as soon as you move forward to helm area, noise levels increase appreciably to a level that would be excessive if you were cruising for any length of time. 
Thanks to those who have sent PM's etc.......it's frustrating but I'm sure I will find a cure!!


Posted By: bricker
Date Posted: 22 Jan 2023 at 3:10pm
Could it be the prop?? 

Wear marks on same position on each blade of prop with spec of 3 x 14 x 17. Boat also came with a 2nd prop.....3 x 13.74 x 21. Pictures below of wear to blade (all 3 blades have similar wear).






Posted By: RogueOne
Date Posted: 22 Jan 2023 at 9:25pm
That is a very strange wear pattern. Almost looks like someone has been playing with it to try to reshape/rebalance.
Throw the second prop on as a test to see if it gets rid of the vibration. Some boat shops will also lend you a prop if you ask nicely.



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