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View Full Version : new impeller, still overheating - help needed


upsidedown
07-11-2010, 05:51 PM
I have an 89 Prostar. Before taking it out for the first time yesterday, I had it running in my driveway with a hose supplying the water intake. It ran about 10 minutes, water pouring out the exhaust normally. I've done this each of the 10 years I've owned the boat before my first time out.

I took it to the river, dropped it in, and left it idling as I parked. When I got back, the temp was nearly 200. There were a lot of weeds at the landing. I motored out to clean water briefly, but no drop in temp, so I pulled it out.

Today i replaced the impeller, but no water coming out the back when i started it in my driveway. I ran it about 30 seconds, then pulled the manifold plugs. Dry on both sides. With a new impeller why wouldn't I be getting adequate raw water? Help. Summer is slipping away and my skis are still dry.

FrankSchwab
07-11-2010, 06:18 PM
Check the transmission cooler. It's likely filled with crap, and will keep water from flowing. Pull the inlet side hose off, and look inside.

It's about a 4" x 12" cylinder between the water inlet on the bottom of the hull, and the raw water pump.

/frank

Cloaked
07-11-2010, 06:24 PM
Check the transmission cooler. It's likely filled with crap, and will keep water from flowing. Pull the inlet side hose off, and look inside.

It's about a 4" x 12" cylinder between the water inlet on the bottom of the hull, and the raw water pump.

/frankPull the output side. The intake side will require you to stand on your head or use a mirrior to look up. Unless of course MC laid it on it's side in that year model.

Actually I'd pull both and backflush the cooler from the top side. Easy enough to do.

Hawksinkalispell
07-12-2010, 12:11 AM
I just had a similar problem, except I didn't run it in the driveway. I pulled all the hose from the exhaust hoses to the intake grate. Mine's a 88 Tristar with a 351. If you cooked the impeller, like I did, you will want to pull the hose from the impeller housing and flush them with water. Flushing the tranny cooler is a great idea too. I just flushed all the hoses and the cooler. I also change the Thermostat, which sounds like a good idea for you too. Make sure to get a marine thermostat, you can make your own gasket if ones not available.

Also make sure all your hoses from the intake grate are seated and clamped properly, my hose after the tranny cooler was suspect. If you don't have a good seal with the hoses/clamps you won't have good suction throught the hoses and therefore no water through the system.

I would really look at that cooler as maybe you got some of those weeds in the cooler and got a restriction.

Good luck.