1991 xr4 150 overheating

[eh350x]

stock engine ,replaced stats,poppet ,gaskets(between powerhead and mid)also replaced exhaust plate gaskets ,,has 2-3 psi at idle ,,break over on plane has round 8-9 psi at 3000rpm ,temp gauge reads 200 and buzzer will sound ,slow back down to idle an temp falls to 180 ,if u dont runon plane, it idles at 140-150 all day ,soon as plane shoots to 200,any ideals other than making a trot line anchor with it,,,and by the way does have low water pickup lower unit and also sure motor isnt to high ,,

 

[j_martin]

Re: 1991 xr4 150 overheating

wrong gasket in pump

poor pump outlet seal

Prop a bit too steep. (WOT rpm too low)

Too close to the equator. (actually it looks like you have the tropical poppet spring already)

What is your WOT rpm and water pressure?

 

[eh350x]

Re: 1991 xr4 150 overheating

everything I have put in parts wise have been for the correct year model ,still possibly wrong I guess and the 3000 rpm is not my wot,that was simply a reference rpm I ran for diagnostic reasons and prop isnt to big its been on here before it started this ,,my wot is 6200 rpm at 76.3 mph with 25p trophy 4 blade ,,this overheating kinda started slowly so I put a water pump in it ,( and just to keep things straight I am a mechanic by trade) I have never been stumped like I am now everything is by the book but yet still running to hot ,,I surrender

 

[eh350x]

Re: 1991 xr4 150 overheating

wot psi 10 at best

 

[eh350x]

Re: 1991 xr4 150 overheating

also pulled the exhaust plates off today to check for restriction,,everything seems fine there to

 

[j_martin]

Re: 1991 xr4 150 overheating

You don't have a restriction problem, you have a water delivery problem.
Either the pump has wrong parts in it (there's a couple of variations),
or there's a bad seal at either end of the water delivery tube,
or the tube is cracked,
or there's air intrusion or blockage below the pump. Usual source is a bad gasket under the pump base, or a fault or crud in the casting.

 

[eh350x]

Re: 1991 xr4 150 overheating

OK,,well that I will definitly check, Boy Id rather take a whoopin than pull that gear case again ,but you have convienced me to check that pump and gaskets out ,Im positive its not the tube or tube seals (there new),,,I realy do appeciate your feed back,will give you some feedback on the results

 

[Faztbullet]

Re: 1991 xr4 150 overheating

If it a stock gearcase that has had a pickup/nosecone added, pull the water pump base and check the fiberglass they fill the stock water cavity with. I have seen these break lose from freeze damage and the pump suction pull it upward and restrict water inlet. When you slow down inlet water pushes it back down. I have seen this several times....

 

[j_martin]

Re: 1991 xr4 150 overheating

OK,,well that I will definitly check, Boy Id rather take a whoopin than pull that gear case again ,but you have convienced me to check that pump and gaskets out ,Im positive its not the tube or tube seals (there new),,,I realy do appeciate your feed back,will give you some feedback on the results

Fazt has some good info too.

I don't have much trouble slinging on the LU, but I employ the wife to hand me nuts, pick them up when I drop them, and turn the flywheel with a wrench when needed. She also gives me a kiss if I don't cuss too much.