89' Bayliner down on power

[Stockcar56]

My son has an 89 Bayliner with 4cyl. Volvo, lower unit is Volvo Penta 275. Engine runs great but he says the upper Bellow rotted and got water in lower unit, so when he tried taking off last summer it was way down on power. I'm pretty good with auto mechanics but never touched a boat, what is in the lower unit that would cause loss of power? Appreciate any help

 

[Scott Danforth]

the upper bellows is the driveshaft bellows


have you removed the drive replaced the bellows? if not, here is what probably happened - the failed bellows allowed water to get to the input shaft and U-joint. the u-joints and shaft rusted up, that in turn ate up the input shaft seal on the gear box and probably the output shaft seal on the PDS housing. the failed seals allowed water to get into the upper gear box and allowed the gear lube to come out. the failed PDS shaft seal allowed the output PDS bearing to sieze up. now your outdrive probably needs bearings, cone clutches, and a bunch of work. and the motor needs to come out to replace the PDS housing bearings

the lack of bellows replacement on a bi-annual basis can lead to the death of the outdrive.

 

[dennis461]

My son has an 89 Bayliner with 4cyl. Volvo, lower unit is Volvo Penta 275. Engine runs great but he says the upper Bellow rotted and got water in lower unit, so when he tried taking off last summer

Has the lower unit had water in it since last summer?

it was way down on power. I'm pretty good with auto mechanics but never touched a boat, what is in the lower unit that would cause loss of power? Appreciate any help

Most of the lower unit and top transmission is gear to gear contact, power goes through or it doesn't.
The cone clutches can slip causing a reduction in power to the prop with very little noise.


I suspect the reduced power is an engine problem.

Do you hear strange noises from the outdrive?
If you are grinding up bearings and clutches and gears causing too much drag on the engine, the RPM's should be lower than normal.

Is engine RPM up above 3500RPM and boat moving slowly?

 

[PiratePast40]

.....the motor needs to come out to replace the PDS housing bearings......

The four cylinder engines only have one bearing and the snap ring holding the shaft in the housing is accessible from the rear. Access to the forward snap ring and seal is the same whether the engine is removed or not. Wondering why people recommend engine removal for this. Is it so the shaft can be hammered out from the forward end?

I can understand the shaft being hung up on the flex plate if rusted together, and that would be a reason to get penetrating fluid onto that spot. You would need to remove the engine, or go through some acrobatics to separate engine from the flywheel housing if that were the case, And for this particular instance with the likely hood of water in the housing, it would probably be appropriate.

But for a normal bearing replacement, on four cylinder engines, don't understand why people recommend pulling the engine.

 

[dennis461]

The four cylinder engines only have one bearing and the snap ring holding the shaft in the housing is accessible from the rear. Access to the forward snap ring and seal is the same whether the engine is removed or not. Wondering why people recommend engine removal for this. Is it so the shaft can be hammered out from the forward end?

I can understand the shaft being hung up on the flex plate if rusted together, and that would be a reason to get penetrating fluid onto that spot. You would need to remove the engine, or go through some acrobatics to separate engine from the flywheel housing if that were the case, And for this particular instance with the likely hood of water in the housing, it would probably be appropriate.

But for a normal bearing replacement, on four cylinder engines, don't understand why people recommend pulling the engine.

We are getting off topic I'm afraid.

The shaft cannot come out the aft end until the three parts behind it come out.
The shaft has a step in it (page 91 of the manual).
It "normally" would be pulled out towards the front after the shaft snap ring is removed.
The three parts are seal, bearing snap ring, bearing.

The bearing is PRESSED in from the stern.
There is no way to get a bearing puller on it with shaft in the way.

Now, if one could make a splined shaft holder strong enough to grab the shaft and pull it out, it would(maybe) pull the bearing.
Perhaps there is an opportunity here, maybe I'll invent a tool before all these older boats disappear.

Another couple of reasons to pull or raise the motor.
Clean out the bilge, replace rear main seal, replace oil pan gasket, flex plate and pilot bushing inspection, rubber center support bushing inspection

Rubber Cushion

804210

1

Obsolete part)

Just my opinions and experience on my previously oil dripping boat.