overheating chevy with volvo outdrive

[klibes]

chevy 350 with volvo outdrive in 77 bayliner overheats quickly when at speed but cools when idleing along. has new water pump (fresh). johnson f5B-9 salt water pump looks good but not sure. any suggestions?

 

[captmello]

Re: overheating chevy with volvo outdrive

Common problem on the old Volvos. Your most likely sucking air into the water intake at the outdrive when the boat is on plane. Check the hose connection at the outdrive. that connection can be bad for any number of reasons. Remove the hose on the outdrive and inspect the fitting for corrosion etc.

Let us know what you find.

 

[cr2k]

Re: overheating chevy with volvo outdrive

Another common problem in Volvo outdrives is the fact that the water flows to the engine through the steering bushings on the drive. If your drive is loose you could be sucking air. At idle/low speeds your drive will still be in water and work OK. On plane drive bushing will be out of watewr and can suck air.

2 Fixes (if this is the case)...

1. Remove the drive and all the related stuff on the back of the boat and replace the plastic bushings.

2. (Easiest/cheapest/best) find a place where you can access the bottom of the hull from inside the boat (blige) with some working room behind the water pump and on same side if possible. Pick up a Scupper fitting (thru hull water intake) and seacock (valve to shut it off in case the hose breaks, etc.) cut a hole in the bottom of the boat (since it's a Bayliner it won't be too thick) install the intake (open side forward) valve and a hose to the water pump. Plug or cap old water hose fitting inside the boat.

Be sure to use plenty of Under Water silicone or Life Seal to ensure no leaks on the hull.

 

[captmello]

Re: overheating chevy with volvo outdrive

2. (Easiest/cheapest/best) find a place where you can access the bottom of the hull from inside the boat (blige) with some working room behind the water pump and on same side if possible. Pick up a Scupper fitting (thru hull water intake) and seacock (valve to shut it off in case the hose breaks, etc.) cut a hole in the bottom of the boat (since it's a Bayliner it won't be too thick) install the intake (open side forward) valve and a hose to the water pump. Plug or cap old water hose fitting inside the boat.

Be sure to use plenty of Under Water silicone or Life Seal to ensure no leaks on the hull.

I've received this advise as well. Have you done this modification? As you say, it may be a viable option.

This poster may only have a corroded intake fitting or bad Oring at the lower unit. I'm sure you would agree that those are eliminated as being the problem before going though the hull.