Overheating Issue at higher speeds

[nickzlb77]

Hey guys,

Have an 87 Sunrunner
VP IO AQ225E with VP 280 Drive.

Runs fine at all RPM while drive is disengaged. Overheats once I start to get up on plane, actually appears to be as soon as the thermostat opens which I would imagine indicates insufficient water flow to keep up.

Had a loose/slipping belt and repaired. Did not help.
Inspected sea water pump and impeller, impeller is a little beat up (outer edges of blades starting to tear, one blade completely torn) so I will replace that the next dry day. Sounds like a slight bearing noise on and off coming from the pump itself as well.

Removed the intake hose from the sea water pump and there seems to be a pretty steady flow of water, although I assumed there would be more water flowing through this hose and that it would be a greater pressure. Resembled the flow of a garden hose without a nozzle of any sort.

Other than the impeller any ideas?

 

[captmello]

Re: Overheating Issue at higher speeds

Check the intake fitting on the outdrive itself. Pull the hose off the fitting right bellow the ujoint bellows. that fitting the hose is on tends to rot out and leak air while on plane.

 

[nickzlb77]

Re: Overheating Issue at higher speeds

Check the intake fitting on the outdrive itself. Pull the hose off the fitting right bellow the ujoint bellows. that fitting the hose is on tends to rot out and leak air while on plane.

Well, checked the entire system back, all checks out (boats in the water). Decided to pull the intake hose off the raw water pump and run a garden hose through it with the drive trimmed up.. Got a lot of bubbles as the boat bobbed up and down. Got in the water with the drive still up and found the hose just dangling.. Part of the water neck broke off leaving the hose connected to nothing.

Safe to say that was my issue.

Unfortunately shes gotta come out to fix

 

[captmello]

Re: Overheating Issue at higher speeds

Unfortunately shes gotta come out to fix

Take advantage of having the boat out of the water and do any routine maintenance that may need to be done.

Including
Pull the upper gear box. This will make replacing the fitting much easier. The gasket below the fitting needs to re replaced as well. the oring side face down.

Ujoints, check/grease/replace

check for play in the drive shaft bearings.

Replace the two orings necessary to reinstall the upper.

http://forums.iboats.com/showthread.php?t=309095