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2002 4.3 GL-A Overheating Issues! Need Help PLEASE!

Rshipman501

New member
I have a 2002 Larson with the 4.3 GL-A engine. Got stuck on the lake due to an overheating issue. Got it home and first step was to replace the impeller. Took it all apart and found less than half a vane left of the 12 on the impeller. Ordered the replacement and once it arrived installed it and tried it out in the driveway. Before long it overheated again. Noticed the hoses did not have good flow. Thought the thermostat was the culprit and figured that was the cause of the original overheating that probably fried the impeller. Ordered the thermostat and after another wait installed it after it came in and it overheated yet again. Read some posts on the forum and looked at volvo pentas site and realized I reversed the hoses on the impeller housing when I put it back together. (this is based on a picture on Volvo penta site, not sure if its correct for my model now) I put the hose going to the thermostat housing from the upper side of the impeller housing. The drawing shows it going from the lower side of the impeller housing to the thermostat. So I swapped hoses and checked the impeller again while I was at it and some more pieces of the old impeller were cleared from the hoses. When I put it all back together and tried it out it now overheats only at idle. At higher RPMs it seems the engine is cooling as the temp gauge does go down. The water coming out the back is coming from both the base of the lower end unit and from the propeller but not as much as before I had issues to begin with. Did I reverse the hoses correctly or do they need to go back the way they were prior to changing the thermostat?? Is the circulation pump the next likely culprit? Or does it sound like a piece of rubber impeller is causing a blockage somewhere?? We have been without the use of the boat for weeks now and I really want to get it back on the water!! Any and all help would be appreciated!! Background the block was replaced by the previous owner and has very few hours on it but I don't know if he replaced the circulation pump or impeller when he replaced the block.
 
Circulation pumps rarely fail
Find the rest of the old impeller
Check for blockages at the small passage in the exhaust elbow where the spent cooling water is dumped into the exhaust stream.
I water is coming out of the exhaust port, hoses are correct on pump.
Impellers die from..
Old age or a diet of sand and gravel.... or... running dry for more than a few seconds.... ( as in hoses reversed !!!)
 
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