Engine overheats after DP-S drive rebuild

[whitesharkseeker]

I have owned my 1996 boat with 5.7Gi engine and DP-S for 16 years and never had an overheat issue. Recently I had salt water in the gear oil so had a mechanic tear the outdrive down and found grooves in prop shaft where seal would sit allowing water in drive. Long story short, after getting shaft spray welded and ground to spec's, outdrive was assembled and put back on the boat. It now overheats when I throttle above 2,000 RPM's and at 3,000 RPM's temp goes to 210 degrees F. It heats up quickly barely a half mile out of the harbor but cools right back down at 1600 RPM's. I know the problem is with the drive, thermostat works and raw water pump is new. Any suggestions or advice? I read that drive ratio can cause those symptoms but makes no sense to me. Thank you.

Eric 22' Davis

 

[Scott Danforth]

On a VP, the drive is a glorified hose regading the raw water. Look at the fitting the hose connects to, look at the raw water impeller on the motor.

 

[QBhoy]

Check you’re power steering cooler. That’s likely on the intake hose from the drive and before the raw water pump port side of engine and under. May have a blockage there. Easily tested by taking the pipe off the pump and blowing bubbles out the drive when blowing through the pipe.
Are the risers too hot to touch ?

 

[whitesharkseeker]

Thank you for the replies. Yes, the risers are very hot, way too hot to touch without burning my hand. I do see light, wispy smoke when it's running hot after I put boat in idle but not sure if that's just exhaust.

Eric

 

[Scott Danforth]

Thank you for the replies. Yes, the risers are very hot, way too hot to touch without burning my hand. I do see light, wispy smoke when it's running hot after I put boat in idle but not sure if that's just exhaust.

Eric

that is most likely the exhaust hoses burning if your not flowing water.

 

[Lou C]

A few other things to check:
the plastic fitting in the pivot housing that the raw water hose connects to...these can crack and leak water or cause air to be sucked in.
the irregular shaped O ring that fits between the pivot housing and the drive
the water tube grommets inside the drive

 

[whitesharkseeker]

Very appreciative. Thank you very much for the help!

-Eric 22' Davis

 

[whitesharkseeker]

A few other things to check:
the plastic fitting in the pivot housing that the raw water hose connects to...these can crack and leak water or cause air to be sucked in.
the irregular shaped O ring that fits between the pivot housing and the drive
the water tube grommets inside the drive

I backflushed the system using a hose connected to the power steering oil cooler and noticed water spraying out of that plastic water inlet nipple or water hose area in the pivot housing. Is that normal? Maybe normal during winterization?

Thanks, Eric

 

[Bt Doctur]

If your backflushing and seeing water squirt out, its not normal .That is where your sucking in air and not water

 

[Scott Danforth]

I backflushed the system using a hose connected to the power steering oil cooler and noticed water spraying out of that plastic water inlet nipple or water hose area in the pivot housing. Is that normal? Maybe normal during winterization?

Thanks, Eric

no, your fitting is broke (common issue) replace it. your overheating because your sucking air.

you also need to replace your exhaust hoses.

 

[whitesharkseeker]

Thank you guys. My mechanic, who I believe not truthful with me now, insisted that water comes out at that fitting and is normal for relief during winterization. The shop manual does indeed show a "drain groove" in that plastic fitting (along with an O-ring) so I didn't know what to think. He said my exhaust flapper valves were stuck causing the problem and he removed them. Told me my plastic water nipple was fine. I think that was just an excuse to charge me more money. Overheat problem started after drive was re-installed after a rebuild. Anyway, appreciate your expertise.

-Eric 22' Davis

 

[Scott Danforth]

volvo penta doesnt use exhaust flappers.

your "mechanic" is full of crap

 

[whitesharkseeker]

Yah, figured that. Pretty sad. Anyway, thank you for your help and comments.

-Eric 22' Davis