1997 Glastron GS 225 Volvo Penta 5.7 GSPLKD overheat on power turns only

[kersfam]

I have a 1997 Glastron GS 225 with a Volvo Penta 5.7 GS engine with SX-C1 Cobra drive. Engine long block replaced 2012. Engine temperature will rise rapidly on "power turns" or when doing figure 8's in lake for a couple of times. As soon as I straighten it out temperature goes down quickly. Can run straight on plane at full throttle with no overheating. Raw water impeller replaced this spring along with new boots and water pick up hose at Transom. Risers and manifolds recently cleaned and riser mount gaskets replaced. This was after an ehaust elbow failure on port side from blockage in thermostat housing to manifold water inlet. Problem started after this failure. Back flushed raw water pump pick up hose. Thermostat housing removed, cleaned and repaired. Thermostat was replaced last year. Re-used. All engine cooling hoses have been removed and flushed. Looking for suggestions on why it only overheats on quick turns only. General or slow turns are OK- slight rise in temperature but no overheat. Thank you to those who try to help!

 

[Bondo]

and water pick up hose at Transom.

Ayuh,..... Welcome Aboard,.... Purely speculation,.... Is the water hose gettin' pinched by the drive in hard turns,....

It might need abit of twist put in, or taken out, so it don't collapse,....

 

[kersfam]

We trailer the boat to various lakes so it is out of water most of the time. I thought of that and looked at it turning drive in both directions. Doesn't appear to be but really hard to see up there. I also thought it might be a cracked plastic fitting the hose connects to. Only way to tell on that is to replace it which I plan on doing this winter. From what I read, if it was a cracked fitting, it would overheat going straight as well. Thank you for your suggestion- I will take a closer look at it again.

 

[kersfam]

Just talked to a VP Tech that I trust. He stated that if it did it in both directions that it is most likely the impeller. VP has a parts bulletin out with new impellers to use. Older impellers are less depth than the new ones and will cavitate under high draw demands. He stated that pinched hoses will only do it when turning left. Bought new impeller from VP dealer and will install this weekend. Might as well pay the couple extra $ and make sure it is right. Parts man said that even the part number in the parts bulletin has been superseded this year. Will give it a try and advise.

 

[kersfam]

I would like to throw this idea out to the group. I replaced my propeller with a 4 blade impeller from the original 3 blade impeller. Would that create a cavitation during power turns causing this? I asked the VP tech and he said no as the water pick up is way before the propeller, at higher level, and cavitation occurs after the propeller. I still have the 3 blade prop and will try it next if new impeller does not fix problem. Just thought I would get other opinions.What do you think?

 

[dypcdiver]

As the Tech said the pick up point is well ahead of the prop. I would be checking the plastic fitting and the associated "O" rings both for condition and POSITION as one of the grooves is drilled also the hose clip for tightness.

 

[kersfam]

Replaced raw pump impeller. One of vanes was flipped backwards. Also reconditioned the back plate which had a groove going from pressure port to suction port. Impeller thickness was same between old one replaced this spring and new one from Volvo. Back flushed the raw water pick up system. Had trim down. Looked normal no blockage- no leaks- came out of water PU ports. Put trim at angle usually used for higher speeds- water leak starting coming out of raw water pick up hose at upper drive plastic connection. I believe I have found my problem. Lowered trim= no water leakage. Raised it again to high speed height- water coming out. Must be sucking air at that position. Will investigate tonight. Difficult area to get into to tighten hose clamp. I hope it is just that. If not- time to replace the plastic fitting. Thanks to all who responded.

 

[kersfam]

Found Plastic fitting cracked 3oo of the 360 degrees. Been that way for awhile as signs of water rust very evident. Replaced it and water pu hose. While having exhaust bellow off, saw old riser flapper wedged into exhaust port which goes out thru the bottom anode. Never knew that before. Removed it. Ran boat on lake for over 8 hours. Ran at top speed and really pushed the boat hard- never went past 175 degrees all day. Even sounds better with the cleared exhaust port.

 

[Bondo]

Ayuh,..... Glad to hear ya found the problem, 'n got 'er fixed up,......