Rattle

[heathstallings]

I have a 1984 Volvo Penta AQ125A with a 270 outdrive. Runs great at idle and low speeds (2500rpms). Once I accelerate to around 3000 rpms and above, I here a rattle coming from the engine or outdrive. I can't determine exactly where it is coming from. There is no noise when in neutral at these rpms, so I would assume it is coming from outdrive. The sound does not change when turning in either direction. The bellows are in good shape and the u-joints were replaced 1 1/2 years ago. Outdrive oil recently changed and saw no signs of wear (metal shavings) in the oil. Any ideas?

 

[Mullin]

Re: Rattle

You need somebody else to drive while you try to listen for the noise I guess.

Mine kinda did a similar thing but I think it was the steering arm loose on the steering helmet. I tightened it down and haven't been back out yet, maybe tomorrow. But mine would stop rattling whenever I turned the wheel a little, just rattled with no tension in the steering at all.

 

[Bondo]

Re: Rattle

I have a 1984 Volvo Penta AQ125A with a 270 outdrive. Runs great at idle and low speeds (2500rpms). Once I accelerate to around 3000 rpms and above, I here a rattle coming from the engine or outdrive. I can't determine exactly where it is coming from. There is no noise when in neutral at these rpms, so I would assume it is coming from outdrive. The sound does not change when turning in either direction. The bellows are in good shape and the u-joints were replaced 1 1/2 years ago. Outdrive oil recently changed and saw no signs of wear (metal shavings) in the oil. Any ideas?

Ayuh,.... Pull, 'n inspect the Spark plugs,.... I'm thinkin' yer hearin' Detonation,....

If so, that Rattlin' is yer motor consumin' itself...

A Lean condition is the #1 cause in boats...

 

[Mullin]

Re: Rattle

^ dang, I hope it's not pre-detonation, that's not good!
Should be easy to fix if it is, adjust carb and verify timing. Also I always run premium gas too, it's really cheap compared to knocking.

I think Bond-o may be right, seeing as it doesn't go away like mine did while turning. It might not happen in neutral, but the motor isn't under a load either. You should be able to tell be pulling the plugs, like Bond-o said.

 

[heathstallings]

Re: Rattle

Ok. Pulled the plugs to inspect. They are completely black. Otherwise look fine. I cleaned them up a little with some emory cloth. They are less than 6 months old, so I didn't replace them. I checked the gap and reinstalled. Tried to start it up, but seems like it flooded out. (could smell fuel) I waited about 30 mins and tried again. Started up, but ran very rough. It would rev up and then down up then down. After it warmed up a bit, it ran a little smoother. Took it to the water to give it try. It was very difficult to keep it running at idle and low throttle. If I could get it passed about 2000rpm it would run fine. Opened it up and ran like a champ. No rattle anymore either. I would bring it back to idle and it would run smooth for a minute or so and then start running rough again. Sometimes it would die while trying to idle. When I tried to start it up again, it would have to turn over more times than usual to start. Then same thing. Idled rough, but if I gassed it, it would go and run great. Not sure what to do next.

 

[Grub54891]

Re: Rattle

Sounds like too much fuel,is the choke opening completely? Check that first,take off the spark arrestor and warm it up on muffs or at the lake,see if it opens up on its own. If that is ok then look down the carb-carefully while its running,should see a mist of fuel from the venturies,no constant drips. If it drips,the carb needs a rebuild.
Let us know what ya find.
Grub

 

[heathstallings]

Re: Rattle

No choke on this thing. It has always been a little hard to get going when cold, but never once it warms up like it is doing now. The carb was rebuilt last year, but I will check on the fuel drip you mentioned.