Ford 2.3lt OMC is overheating at idle.

I have a 1987 Larson Citation I have restored completely but I am not a mechanic. The boat runs great, however, if idling for a long time the boat will get too hot (230). I have replaced the thermostat and I looked at the impellor and it is fine. I flushed water through all passages and they are clear. Here u=is the crazy thing. On the muffs it runs great and will not get hot. Is it the water pump?? as soon as I get the boat above 2k rpms (on a water test) the temp drops way down to like 120. Any Ideas??

I had the same problem with a 4.3 v6 and it was the water pump in my leg. It also looked good but if you take it off and put a straight edge on the face of the pump you will probably find that there is a gap between the impeller and the edge allowing water to bypass at low rpm but at higher rpm it will put out enough to cool properly.

Also when running with the ears on don't put too much pressure on the tap as this will force water past the water pump seal into your drive.

So are you saying it was the water pump on your motor??
If so I think I found one for 25$ I will install tomarrow. The impellor in the drive is new.

Also there seems to be no grey area. If I am running at 1500rpm temp is climbing to 220. At 1800 temp will not get to 130.

Did u change the seal on the impellor housing? Make sure it hasen't come out of the groove. And make sure the metal plate isn't scored/warped. Are u sure the impeller is good? They sometimes take a set & have to be replaced.

No mine was the pump in the leg. I have transparent jugs on my intake hoses and can see water and or bubble flow. This shows the difference between high and low rpm.

KPG you were right!! After cleaning off old gasket material I found that someone has chipped the edge of the impellor gear housing where the paper gasket meets the drive. This means I have to get that gear housing (impellor mounting plate??) out. This is not the metal gasket. This is the shaft gear housing that the whole impellor assembly mounts to. After removing the bolts, it is still frozen in place. Is there a technique or tool I need for this??

yes a hammer.

1987larsoncitation said:

KPG you were right!! After cleaning off old gasket material I found that someone has chipped the edge of the impellor gear housing where the paper gasket meets the drive. This means I have to get that gear housing (impellor mounting plate??) out. This is not the metal gasket. This is the shaft gear housing that the whole impellor assembly mounts to. After removing the bolts, it is still frozen in place. Is there a technique or tool I need for this??

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Are u referring to the adaptor that has 2 bolts? If yes, well that sucker can be a bear to get out. Soak the crap out of it around the housing with PB Blaster & let it soak in for a few minutes. Get a razor knife & go around the adaptor with it. There's an 0-ring inside the adaptor that is holding it in place. Now get a pair of vice grips & try tp pull it out, it can be a s.o.b. but it will come out. If I were u I would replace the oil seal {which may or may not come with the new adaptor} & u will definately need to replace the 2 0-rings for that part plus the gaskets.
When u put it all back together, don't overtighten the impeller housing bolts or u can warp the stainless steel plate. Good luck!