View Full Version : 1991 force 120 outboard over heats at full throtle

05-27-2009, 04:25 PM
"I think it is the impeller, yet that was changed 4 years ago. I have changed the T stat and reset the timming with a timming gun. The engine runs great, idles and mid range even full throtle. But run at wide open for longer then 2 mins and the over heat alarm goes off. I am planing on changing the impeller have order the parts for thursday, just seeing if im right in my assment of the problem. Side note the stream behind the boat decreases as the rpms increase."

05-27-2009, 08:33 PM
Two years on the impellar is when I change.

05-28-2009, 06:43 PM
"if the impeller is 4 yrs. old that would be my first thought. i would get a temp gauge too... if you have heat issues then it is nice to how what that heat is.... that is just my opinion and i could be wrong, i was wrong once before."

05-29-2009, 08:43 AM
Really you change the impeller every 2 years. Wow I thought they would last longer then that.

05-29-2009, 11:45 AM
"Nope, every 2 years and every second change go with a kit (including gaskets and seals) - it's cheap insurance against a blown powerhead due to overheat."

05-29-2009, 04:45 PM
"Oh yeah I bought the kit anyways. New gaskets are always better and for 10 dollars more, I will take the piece of mind."

05-30-2009, 02:50 PM
"Ahh I took it appart and have found the problem, the pressed sleeve in the impeller housing has come free. The old impeller is stuck on the shaft. Does anyone know where I can by a new sleave?"

06-02-2009, 08:23 PM
"You should just get the entire pump kit. It will include the lower seal / wear plate,/impeller/and pump housing.

Find the key way slot looking down on the impeller and put a wood chisel there and cut the old impeller off. They don't work if they don't free float on the shaft. So clean the shaft down to bright metal before installing the new impeller-use grease on everything to avoid a dry start, and spin the drive as you tighten the pump housing so you don't pinch the impeller."

06-03-2009, 08:48 AM
"William I have been searching for a new impeller housing and bearing kit for the drive. After taking it apart I found the problem, The bearings in the shaft are worn and there is generous play. This caused the metal sleeve that houses the impeller to break free and become ovaled at the top of the housing. I need a lower end rebuild kit and housing for the impeller. If anyone knows where to find one, please let me know."

06-03-2009, 05:24 PM
"You can buy a remanufactured gearcase at
www.obrparts.com ("") ."