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Please help 1987 blackmax 200hp overheating

jsmooth

New member
"the motor seems to be overhea

"the motor seems to be overheating as the temp horn comes on so i bought a new sensor because the old one seemed to be faulty and would come on around 165 degree's.motor has new head gasket's,water pump,and t stats.motor was sitting for a long time before i got and the carb's need to be redone i think cause it run's a lil ruff on idle and i haven't changed the poppet valve yet either.can someone please help with this.water comes ot of pisser good at idle and low rpm's bit the start's to fade a lil when you go over 3,000 rpm's and the horn comes on"
 
Spend the 20 bucks or so to re

Spend the 20 bucks or so to replace the poppet.

The thermostats take care of the cooling up to about 1500-2000 rpms then the poppet takes over until near wide open throttle.

Sounds like it could be your issue....
 
thank's graham for the qui

thank's graham for the quick response.do you think that the carbs running lean and needing to be rebuilt could cause this issue also?i was also told that the poppet and stats are open when your at full throttle is that true? thank's
 
"The cooling system works on &

"The cooling system works on "pressure" produced by the water pump. Up to about 4 psi (around idle speeds) the thermostats do their thing to get the motor to it's optimum running temp.

Between about 4-9 psi (anywhere from about 1500 rpms up to 4000+ depending on the model), the poppet opens (to the degree of pressure against it) to regulate the flow of cooling water.

Above 10 psi (normally about 12 psi at wide open throttle), the poppet is fully open and the water flows unrestricted through the power head (in theory).

If you have a clog in the water tube, or a pinhole in it, crud in the waterjackets (salt/sand/silt/mineral build-up) etc, that could restrict the waterflow and cause an overheat issue.

Running lean is never a good thing. Yes it can create more heat, but that heat is generated because the motor is not getting enough lubrication - which before long will cause a major failure costing possibly thousands to correct.

So if you have a carb issue, have it looked at immediately as well..."
 
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