mercruiser 260 overheating

[BrockR]

i had the boat out last weekend and as i was headin in for the day i noticed that the engine was getting a little warm so i shut it off and we walked it the rest of the way to shore. i hooked it up to the muffs when i got home and it was for sure overheating so i started with the raw water pump and that didnt help, so next i tried the thermostat and still got hot, so finally tried circulating pump and its still over heating im about to give up!!! i tried some troubleshooting, all hoses are good, exhaust manifolds and risers are good, the one thing i found is that if i take the 6 hoses off of the thermostat housing and just let water circulate thru the engine then it stays cool but if i stick the hoses back on then it starts to overheat??
Thanks in advance, im goin nuts it is over 90* here and im ready to go to the lake

 

[Bt Doctur]

Re: mercruiser 260 overheating

clogged manifolds or clogged risers

 

[BrockR]

Re: mercruiser 260 overheating

i have thru hull exhaust on it and its puttin out water could this still be a manifold or riser issue Doc?

 

[BrockR]

Re: mercruiser 260 overheating

i took the manifolds and risers off again and they are clean. Im truly stumped ive never had an issue like this. Are there any other possibilities that im not aware of or could have been overlooked? when i ran the enine with all the hoses off of the thermostat housing, how much water should be coming out of the housing constant pressure or stop and start?

Thanks

 

[fossill]

Re: mercruiser 260 overheating

gauge is OK?