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Maud

Overheating on muffs

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My chap is overheating on muffs. Has new circulating water pump, manifolds, risers, & impeller. Only overheats while in neutral when you rev it up. Hasn't been swimming since we bought it & new parts were installed. Will that make a difference?

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When on muffs, you shouldn't really go above an idle, the impeller can suck in more water than your hose can deliver...

wncrjb

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What about the strainer on the port side of transom, does water take up there too?

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Rev it once to activate the altenator and then only let it idle ... your hose will never deliver enough water to cool the engine.

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Noted.... So is it water test time!?

Yes if it only overheats at idle on muffs.

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If it overheats at idle on teh muffs, you have an issue. If it does not, spalsh it and run it.

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Mercruiser's technical bulletin recommends water at half-way valve open and idle at 1300 RPM until warm up. More pressure than that on muffs will only shoot water out the sides of the muffs. Higher RPM can overheat the engine. Hy

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Rev it once to activate the altenator and then only let it idle ... your hose will never deliver enough water to cool the engine.

Phillbo....

Never heard this. Can you explain ?

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I stopped using muffs on my B3. Just couldn't get enough water in. Water shooting out the sides, muffs sliding off, etc. So I use a large plastic storgage bin, slide it under the drive and fill it with water till the intakes are submerged. Then I just leave the hose running low pressure in the tub. Much more reliable than the stupid muffs!!

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That was the way we use to test our outboard motor when I was younger.

redneck-jacuzzi.jpg

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I was actually just thinking about this. I was told some time back, before i had a BIII, that the muff for a BIII were different/bigger than the Alpha. I have muffs i used for my Alpha and i wanted to make sure everything was running correctly before i put her in the water for the first time. Not a lot of boats out on the river this time of the year to assist if you need help. I think I'll try the storage tub idea.

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My dealer also said you need different muffs for BIII. He sold me the muffs that have asmall rode that goes through the water intakes and then you slide each side together to get a tight fit .

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