Volvo Penta AD41 Engine Mounts

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orion1210

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Hi,
My port engine generates a bit of vibration at idle and was considering replacing the mounts as they’re likely 30 years old. It has the dp290 drives.

Am I right in thinking that they only have forward mounts when coupled to an outdrive? If that is the case, is their anything isolating the engine from the hull or is it a direct connection through the bell housing to the transom shield?

if anybody has any tips on replacing in situ or can recommend any suppliers I’d appreciate it.

thanks
 
Are the mounts definitely gone ? Or is the engine vibrating as a result of idling too low or running issues ?
 
I’m going to have a good look next time I’m at the boat, just armchair’ing it at the moment.
If I adjust the idle back to 600-700 as indicated on the Volvo guage I get some vibration, but have read they can be inaccurate and that the engine will vibrate if too low. I’ve ordered a optical tacho to x-check next time. I also get some mild vibration at certain rpms, which might be down to mount harmonics. No other issues that I’m aware of. The other engine is always smooth, well as smooth as diesel gets.
 
on my ad31 I'm under the impression from discussions with my engineer that there are 3. One at the back and 2 at the front. Which I am waiting for him to replace, as one of them has completely gone.
I'm guessing the ad41 will be similar.
 
Just found this in an online manual for ad31p

Engine mounting — Flexible mounting which provides sound and vibration insulation. The engine has two adjustable rubber mounts in front of the engine and rubber suspension between flywheel housing and transom shield
 
hi everyone,

I have a nimbus 26DC, with an ad41 on a Volvo Penta sterndrive. I'm looking for a way to reduce engine vibration/noise the engine is running at optimal rpm and the sound isolation is efficient and in a good state. I noticed this form and I have the same thought, my engine mounts just turned 30 years old, would new ones really make a difference? Does anybody have experience with changing to new engine mounts on an ad41,ad31,kad32,kad43/44, or any other older diesel engine on a sterndrive?

kind regards The bushman.nimbus motor voor op forum.jpg
 
the bushman said:
hi everyone,

I have a nimbus 26DC, with an ad41 on a Volvo Penta sterndrive. I'm looking for a way to reduce engine vibration/noise the engine is running at optimal rpm and the sound isolation is efficient and in a good state. I noticed this form and I have the same thought, my engine mounts just turned 30 years old, would new ones really make a difference? Does anybody have experience with changing to new engine mounts on an ad41,ad31,kad32,kad43/44, or any other older diesel engine on a sterndrive?

kind regards The bushman.View attachment 135843
Click to expand...
that paintwork looks in amazing condition for 30 yrs old
 
the bushman said:
hi everyone,

I have a nimbus 26DC, with an ad41 on a Volvo Penta sterndrive. I'm looking for a way to reduce engine vibration/noise the engine is running at optimal rpm and the sound isolation is efficient and in a good state. I noticed this form and I have the same thought, my engine mounts just turned 30 years old, would new ones really make a difference? Does anybody have experience with changing to new engine mounts on an ad41,ad31,kad32,kad43/44, or any other older diesel engine on a sterndrive?

kind regards The bushman.View attachment 135843
Click to expand...
Props damaged ?
 
I had vibration and wobbling on a shaft drive version of that engine and new mounts made a big difference. It may not work on an outdrive but I was able to verify defective mounts by marking the top of the engine and measuring a definite and considerable movement forward when put in gear.

D
 
First of all, thank you guys for all the advice,

the engine is repainted once in its lifetime if am correct.

Prop damage could be a thing we have 2 little dents in one of the props, but the vibrations are there when the engine is running in neutral.

@bowler thanks for sharing your experience, sadly on the sterndrive that's quite difficult to test but certainly going to check for any excessive movement while shifting. If we change the engine mounts I will report back to you guys, for now, if anybody else has experience with changing their engine mounts on an ad41 I would love to hear it.

kind regards,
The Bushman.
 
the bushman said:
First of all, thank you guys for all the advice,

the engine is repainted once in its lifetime if am correct.

Prop damage could be a thing we have 2 little dents in one of the props, but the vibrations are there when the engine is running in neutral.

@bowler thanks for sharing your experience, sadly on the sterndrive that's quite difficult to test but certainly going to check for any excessive movement while shifting. If we change the engine mounts I will report back to you guys, for now, if anybody else has experience with changing their engine mounts on an ad41 I would love to hear it.

kind regards,
The Bushman.
Click to expand...
Robush is were to buy.
 
So it wasn't the mounts or too low rpm in my case, after checking with an optical tach. I also checked/adjusted the valve clearances.

I'm now considering a failing lift pump (particually so as I have a feeling my oil level has increased slightly) or a bad injector. I've read of similar vibrations being remedied with a lift pump replacement. Also plan to crack the injector line fittings one at a time to see if I can identify a bad cylinder or trapped air and also swap the lift pumps between engines. The vibration gets progressivly better upto approx 1200rpm where it clears completely.

I've also recently noticed that the suspect engine lags a little when getting onto the plane so am also going to take a look at the turbo and exhaust elbow. Hoping it's not a piston compression issue.

Regarding the injectors; is it possible to still have some air in a injector line hindering operation since the last filter change despite putting some hours on at close to WOT? Also, what is the likelyhood of being able to remove an injector (using a suitable pressout tool in contact with the steel sleeve washer) without rendering the copper sleeve requiring replacement?

Appreciate any advice
 
Use your nose to check for oil dilution you will smell normally the fuel

removing an injector is Sod’s law do it by the work shop manual with the correct tools is best but can still disturb the sleeve
you could try loosening each pipe in turn and compare ref drop
dont take nut off and use rag to stop diesel spill
 
So I'm none the wiser. No comparable difference between cracking each injector nut. I can't detect any diesel in the oil either. Vibration seems to be getting more pronounced or I just focus on it more!! Completely clears around 1000rpm though. I might revisit the mounts and go from there.
 
You check the prop ? If it does it at low rpm and again at higher rpm…it’s something rotational. Prop would be the favourite
 
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