Hot Engine

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Bob

A couple of weeks ago my engine overheated to the point where it peaked off the temp guage due to a broken belt. I have replaced the belt and chnged oil but the engine is now running very hot. When the engine is not under load it can run, so far as I can tell, indefinately without overheating but, when the trans is engaged and it runs at 2000 rpm for 40 - 50 minutes the temp goes up to 230 with no sign of stopping. I have checked the flow of fresh and raw water and that appears to be adequate. Have also checked the impellor which is fine. I am concerned that there is internal damage to the engine. Any suggestions or comments would be appreciated.
 
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Rhet Tignor

Air trapped in the engine

You don't offer much info on the type engine in your boat. However, I have a 25XP with out an overflow tank and experienced overheating much as you describe. Turns out I had air bubles. My solution was to (I'm not sure I can explain this correctly) disconnect the hose coming back from the hot water heater and fill the fresh water system until water/antifreeze solution came out of the hot water heater return hose. With that done all of the air locks were gone. My engine has run vry well for one year. I might add that someone (on the web)suggested that I install an overflow tank kit. I ended up not doingh that, but I check my fresh water system a lot more than I used to. Hope this helps.
 
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Bob

Thanks

Thanks Rhet I will try to look for air bubbles as you suggested. I do have an overflow tank but, frankly am not quite sure how it works. The engine I have is a Universal 25 just like yours.
 
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Tim Dranttel

Hot Engine and Overflow

Due to your overheat you probably did create steam/air pockets that may be causing your problem. The hot water heater hose thing works pretty well although you may have to do it up to three times before you get rid of all the air. The universal manual says that another way to get rid of pockets is to rev the engine to 3000 RPM in neutral when the temp reaches the normal range. Additionally you may want to look at the radiator cap and thermostat as they may have been damaged during the initial overheat. As far as the overflow bottle goes, it has a check valve in the hose just before it T's into the hot water heater supply line. It allows fluid to flow into the coolent system to allow for loss. If the jug goes empty you can suck air into the system. Hope this helps Tim
 
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Larry

In Hot Water??

I just fixed this exact problem, I have a universal 11hp engine. It would also run fine with no loan but as soon as we moved her she would overheat. The solution, water pump was rebuilt as I had a small water leak, replaced all hoses, were not blocked but had small amounts of debris, changed thermostat, it was not broken but it was old and rusty and finally the main problem was a blocked manafold, we took it to a radiator shop were they boiled all the crap out overnight. It took me 2 weeks to figure out the problem. I have no hair left now, I would suggest checking hose after water pump for flow and thermostat. if all fine take thermostat housing off manafold and run engine for a few seconds only, if water comes out the manafold is not blocked. Total repair costs 125 rebuild waterpump 40 new hoses 20 new thermostat 40 boil out manafold all prices in us easy to fix yourself, I had a mechanic install manafold for correct torque, everything else was done by me. Good Luck to You
 
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Bill Byrd

Ditto Tim's Comments

I had the same thing happen to my Universal M-18 (14 HP). It has an overflow tank. I tried slowing down the engine speed, but that only marginally helped, so I got the engine manual down for a night's study. Topping off the overflow tank and reving the engine to 3000 RPMs a couple of times did the trick. The engine temperature actually came down rather rapidly. Now, I just make sure that the overflow tank is full, and have no more problems - air in the lines. Fair winds... S/V Eagle's Nest bb
 
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Bob

More thanks

Thanks to everyone for taking the time to respond. The suggestions made make a lot of sense to me. Just as soon as I can get back to the marina I will give them a try and let you all know if I have any luck.
 
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