Volvo Penta 5.0fl runs hot when I get on plain

[scruzz]

My engine runs hot when my boat gets on plain. It drops back down when I go back to idle or cruise at a slow speed. Have a new rwp installed and a new thermostat I just put in. Ran it and watched the hoses none of the were collapsing. Pulled the hoses off of the thermostat housing and water was flowing. any other ideas on what to check next? has an xp outdrive.

 

[Don S]

Re: Volvo Penta 5.0fl runs hot when I get on plain

What is your full engine model number or the Volvo serial number. Never heard of an xp drive is either.

 

[scruzz]

Re: Volvo Penta 5.0fl runs hot when I get on plain

It was a little hard to make out on the tag. Hope this is right.
top 4110114268 bottom 0860104 and the outdrive is a sx.
They had a set of numbers on the top and some more on the bottom.
don't know if it is one full # or 2 seperate so that how I wrote them above.

 

[Don S]

Re: Volvo Penta 5.0fl runs hot when I get on plain

Your full engine model number is 5.0FL PHUE, The HU indicates the model year of the engine.
I would pull the risers and inspect the water passages for corrosion and rust. Especially if you boat in salt water. If they start plugging up, it reduces the flow of water thru the engine.

 

[scruzz]

Re: Volvo Penta 5.0fl runs hot when I get on plain

Ok thanks, should I pull just the raiseres or the exhaust manifolds also?
I will try that when I get off Tues.

 

[Don S]

Re: Volvo Penta 5.0fl runs hot when I get on plain

JUst the risers. There aren't any water passages between the manifold and head where it bolts onto the head.

 

[scruzz]

Re: Volvo Penta 5.0fl runs hot when I get on plain

I pulled the risers and they look good no bad rust. I haven't done the clear hose test yet but I undid the hoses from the thermostat housing that go to the the exhaust manifolds and they had pressure coming out when I loosened the hose clamp and pulled the hose off. I also ran a wire into the slots on the exhaust manifold and it didn't seem to be to bad. Any other suggestions?
The only other thing I havent done was changed the circulation pump on the front of the motor.

 

[mcleaves]

Re: Volvo Penta 5.0fl runs hot when I get on plain

You gotta do the clear hose test. You could be sucking air someplace.

Also last year I installed a new T-stat that was bad out of the box it happens.

You also mention a new RWP. Did you installed a new PUMP or a new impeller? I ask because there are issues with some VP impellers and you can get the wrong one that will still fit but leave a gap causing a vacuum loss. If you got a new pump and ordered your impeller separate you could very well be in this boat..

M

 

[scruzz]

Re: Volvo Penta 5.0fl runs hot when I get on plain

ok, I will have to get 2 new riser gaskets and will have to go and get some clear hose. I did buy a new pump couldn't find the rebuild parts it was leaking by the shaft bought a new pump to be sure. What is a t-stat? where should I put the clear hose on the output side of the rwp to the thermostat or between the intake side and the oil cooler? or just hook both up with clear hose? How may bubbles are to many?

 

[mcleaves]

Re: Volvo Penta 5.0fl runs hot when I get on plain

t-stat = thermostat

As for the clear hose you need to put it in several places. The first being the intake/input line to the RWP (raw water pump).

Have you had the drive off? If so you could be sucking air where the water intake gasket is on the gimbal housing mating surface. That part of the drive is exposed to air when on plane. Actually that's a place to check whether you ahve had the drive off or not..

The clear hose on the intake will tell you if you are getting air on the drive side


M

 

[scruzz]

Re: Volvo Penta 5.0fl runs hot when I get on plain

Put a new t-stat also. It was leaking water at the bottom of the transom assembly and the shop pulled the engine and tightened it up. That may be the problem because it didn't run hot before.

 

[Raffo]

Re: Volvo Penta 5.0fl runs hot when I get on plain

I had the same problem with my boat. As soon as the boat plained the temp would climb high. When I got off plain the temp would come back to normal almost immediately. I have twin 290 DP's. There is a water connector on top of the out drive that connects to a hose that runs to your water pump. Mine was corroded and left a hole so that when I plained the connector was above water and sucked down air. As soon as I was of plain the connector was under water and the hole filled with water cooling the engine.

Good luck.
Raffo