Volvo Penta aq125a grinding noise

[Cjp13021]

So I have an 84 Bayliner Capri Volvo Penta aq125a /aq270 out ...I've posted a few times about it... have a few more things was wondering if anyone can help...first of all there's a loud grinding kind of rumbling noise somewhere around the engine that gets quieter when open throttle but louder at idle....I don't feel any shaking on the gear bellow so I don't think it's ujoints......maybe primary drive bearing and bell housing bearings ? ...not sure....also....At low rpms or real slow speed, the gauges fluctuate sometimes and the engine either tries to stall out or does stall out after they all drop down and then bounce around at the bottom for a minute ...but not all the time and only at low rpms .has never happened when at cruising speed...any ideas on either of these issues ?

 

[jerryjerry05]

You posted: maybe primary drive bearing and bell housing bearings ? ..
I'd pull the top of the drive and inspect the drive shaft.
The 125 has 1 bearing and that can be serviced from the outside.
On the top/back of the bell housing is a grease fitting that most people don't utilize or even know it's there??
That fitting lubes the single bearing on the drive shaft.

 

[jerryjerry05]

http://www.volvopentastore.com/mall/image/view/7/8/7464_4.png

This is a parts breakdown for the 270 drive.
Your lucky as if the motor was a V-8 you'd have to pull the motor to do the service

 

[Scott Danforth]

the process for the V8 PDS shaft is in my thread here. https://forums.iboats.com/threads/pds-shaft-issues.687012/

 

[Cjp13021]

Well I pulled the drive when I changed bellows and I couldn't get the yoke out if there .....so I had to disconnect the whole gear box and change bellows that way....but I've had it out on the water moving around now so I'm gonna try again and see if that will come out now. I'm thinking it has to be that bearing because if it was a spun engine bearing it wouldn't be driving 25-30 mph & that bearing is the only thing that I can think of that's constantly spinning in the drive all the time....thankyou guys

 

[Cjp13021]

Yeah I found that grease fitting a few weeks ago...several shots of grease did quiet it down a bit so I'm thinking that's my noise....anybody on why the gauges would fluctuate at low rpms sometimes and engine try to stall ?

 

[baker556]

Gimbal bearing, replace it - not too difficult as a DIY.

 

[jerryjerry05]

No gimbal bearing, they have a drive shaft bearing.
Lot different that the Gimbal replacement.
The V-8 drive shaft replacement is way harder to replace than the 4cyl.

 

[baker556]

Didn't know this Jerry - everyday is school day thanks