marine engine mystery

[jdwjohn]

I have a 2013 Volvo Penta 350, 225 horse in a four winns boat. The engine was running fine. The next time I took it out, it acted like a car with the clutch slipping. The engine was revving but the boat wasn't going as fast as normal. At 4000 rpm the boat would normally be at 37 mph. With the problem it runs at 30 mph. The boat when running normally at wide open throttle max's out at 5000 rpm. With the problem, it wants to rev way past 5000. I took to a repair shop. They ran the boat and it ran fine for them. The next 3 times I took the boat out it ran fine for me. I took the boat out yesterday and the problem was back again.

Any suggestions. Thank you.

 

[mvn]

I would first check the prop hub for slippage.

Mark

 

[jdwjohn]

If the prop hub is the problem, could it be intermittent? After the first time this happened, it ran fine 4 times before it happened again.
Thank you for your help.

 

[Scott Danforth]

Did you forget to drop the drive?

 

[jdwjohn]

Nope drive was down. I wish it was that easy. Thank you

 

[QBhoy]

Cone clutch/water in gear oil ?

 

[jimmbo]

350/5.7L and 225hp? That doesn't add up

 

[QBhoy]

350/5.7L and 225hp? That doesn't add up

Must be a 4.3 gxi at 225hp maybe ? Closest VP 5.7 I can think of is the gxi flywheel rated 320hp…at that age.

 

[jimmbo]

Mine is a 260hp with 2bbl, about 290-300 with 4bbl

 

[QBhoy]

Mine is a 260hp with 2bbl, about 290-300 with 4bbl

Sorry. Suppose I meant at about the age he mentions

 

[QBhoy]

Mine is a 260hp with 2bbl, about 290-300 with 4bbl

Yours is fancy though

 

[dubs283]

Cone clutch/water in gear oil ?

Have never experienced it myself but have heard reports of clutch slippage when using high perf lube in place of GL-5 in SX/A model drives

AQ will run pretty much anything proper weight save for the old single prop which uses 30 wt motor oil

 

[QBhoy]

Have never experienced it myself but have heard reports of clutch slippage when using high perf lube in place of GL-5 in SX/A model drives

AQ will run pretty much anything proper weight save for the old single prop which uses 30 wt motor oil

Agree. But the AQ 290 and similar are famously guilty of taking water in through a failed or nipped gear oil drain fitting. That will cause a slip. Happened to mine years ago. Started sealing up the fitting after an oil change each year. Never an issue since.

 

[Donald0039]

Prop hube or coupler. But usually once a prop hub slips it will never work OK until it's repaired.

These tests you have run have same number of people on board and roughly same amount of fuel?

 

[Scott Danforth]

Could be low gear oil level and the cone clutch is slipping