MFG piper 1500.,1979 over heating low RPM at high RPM, back to 160 degrees

[hammond1979]

Hello all,
Please note that i am new to boating,

I have a mercruiser 120Pk MFG piper 1500 i think its a 1980 model engine (engine numer is 5762851 (if this helps)

engine has been running great i have changed the oil filter and oil i have also changed both petrol filter,Cleaned spark plugs set carb,

Now all of a suddern(maybe because i hit some muddy shallow water) the temp goes above 220 degres at 900 rpm,

If i increase the RPM the engine 2000 seems to settle back to the 160 degrees as before,

I have checked and cleaned the theomastat,tried running the engine without the thermo but the heat still hits 220 now,
can anyone out there help me on this issue,

would or should i be looking at the inpeller ?Also i have blown down the pipe that leads to the inpeller and see bubbles coming out of the stern drive (if this helps i do not know),

any help or advise to a novice is very welcome

 

[*EdC*]

Re: MFG piper 1500.,1979 over heating low RPM at high RPM, back to 160 degrees

Sounds like you sucked up some stuff. I don't know much about I/O's try a through flush. A manual might give you some help.

 

[pduquette]

Re: MFG piper 1500.,1979 over heating low RPM at high RPM, back to 160 degrees

I agree with the concencus - pick up a manual and a new impeller kit , you never know how long it's been since it was changed ! (Great prices +speedy service here at iboats) peter

 

[hammond1979]

Re: MFG piper 1500.,1979 over heating low RPM at high RPM, back to 160 degrees

Hello Guys,

Thanks for the advice ,

Will be replacing the inpeller this weekend and will let you know how i get on

 

[hammond1979]

Re: MFG piper 1500.,1979 over heating low RPM at high RPM, back to 160 degrees

Just to inform all,

the inpeller was the issue plus the water guide pipe had melted,

Now the motor is running weel keeping just at 120 degrees after running the engine for 30 minutes at 1000 rpm,

thanks for the feedback on this matter ,

Now just to re- set the carbs

regards

Wayne