Volvo 5.0FI sx series overheats in river not on muffs

[Shutto80]

Hello everybody I just bought a 94 regal with the Volvo 5.0 sx series outdrive. I'm new to the inboards but test drove the boat and it run great. Bought it and me and the wife took it out for about 3 to four hours and it run great took it home and went out 2 hours later and it run hot within 10 minutes. Had to get towed in and put the muffs on it at home run great. Took it back out and run hot in river. Impeller looks to be in good shape any suggestions? Any response would be greatly appreciated . Thanks

 

[Maclin]

Re: Volvo 5.0FI sx series overheats in river not on muffs

The risers or exhaust manifolds could be corroded and plugged, that will cause overheating at the mid to higher RPM's. The spent cooling water needs to have a good exit or it stays in the system too long and overheats.

If it ran hot on plane, then cooled down ok at no wake speeds then I would suspect the raw water path thru the drive to the raw water pump is allowing air to come in and lose suction. But this problem would probably occur on the muffs also.

 

[Shutto80]

Re: Volvo 5.0FI sx series overheats in river not on muffs

Its running hot just idleing in the river when the muffs are on waters comin out near the transom out the outdrive the water comin out is right warm any suggestions on where or how to start lookin for the problem

 

[wire knot]

Re: Volvo 5.0FI sx series overheats in river not on muffs

Recently had overheat issuse similar to yours. Turned out to be the pump impeller, easy fix. Could be the hose forces enough water to keep her cool. The same COULD be happening on plane.

Extremly easy to check if you got a crank mounted water pump.

WK