99ox66,overheat

[erniefish]

i have cleaned the poppet valve, strong pee stream, but still overheat at idle /troll, any help would be appreciated thanks

 

[rodbolt]

Re: 99ox66,overheat

did you remove the grommet,carefully clean the pocket and install a new grommet ?

 

[erniefish]

Re: 99ox66,overheat

rodbolt, thanks for your reply, to be honest i did not do that , but it was spottless, inside, i will take apart agian if necessary,thanks eric

 

[rodbolt]

Re: 99ox66,overheat

the issue is usually if the popit leaks at low speeds it dumps water pressure. at speeds blow about 1100 it dumps enough that the top stbd cylinder is not kept in cooling water. the tell tale stream on that engine hould be strong enough at idle on the muffs to just bout dig a hole in a concrete pad. if its not find the leak.
also make sure the T-stats are there. they can cause low speed overheats if missing as well.

 

[erniefish]

Re: 99ox66,overheat

thanks rodbolt, i am working on it today,

 

[akmoosehauler]

Re: 99ox66,overheat

Also check your head gaskets. They like to dry out and leak.
Look into the cylinders with a flashlight and see if one of them is clean with little or no carbon. The same thing happened to mine and ruined the motor.
When i checked the heads the gaskets were dryed out.

 

[jersey kr]

Re: 99ox66,overheat

G"day from West Australia,sorry to hear of problems with your motor,I have a 200 0x Yamy and I have the exact same problem,went to flush it after a dive and no tell tale also the buzzer went off, closed it down checked everything and was sure I had done the flushers right and the hose pressure was good,tried again same thing? could you please tell me how you went with your troubles and what the gromets are,i'm not all that confident with mechanical work but I do have a go if I can get the right info I have just bought a Grady White with the 200ox 1999 mdle
I wish you and your family and friends a safe New Year and many hours of happy boating. kind regards Keith