force 120hp overheating

[jiffyboat]

my 1992 force 120hp seams to getting overheating, after running on the water for 10-15 mins, the alarm under the dash go off, and don't stop, , I just replaced the impeller, I bought this boat and it was seating for years, I cleaned the carbs and it fired right up, fist time I checked the compression before cleaning the carbs it was 120psi, and after running on the river it was like 140psi, ...could this because of carbon on the rings?..I'm also thinking to change the t-stat, it pumps a lot of water when riding and the head seams hot..any sugestion..thanks

 

[shytownborn]

Re: force 120hp overheating

try taking the thermostat out and run it ,see if it over heats, sticky rings wont cause overheating

 

[jiffyboat]

Re: force 120hp overheating

thanks for the idea I will try that

 

[john from md]

Re: force 120hp overheating

As for the compression, do a decarb on the engine and the compression should come up. Then do one every season to keep the carbon down.

John

 

[boone68]

Re: force 120hp overheating

i just replace my exhaust plate gasket and i found some sand and corrisons in there it could be clogged

 

[swick]

Re: force 120hp overheating

I have a 99 force 120 that just overheated on me in the water. The impeller is relativley new, but the thermostat was not. There was no alarm or anything, just a lot os smoke and sizzling, after having it in the water for only 5-10 minutes.

I'm pretty sure that i ruined the starter trying to get it running again before calling my neighbor for a tow. Hopefully all I did was ruin the starter. Anyway, I pulled the thermostat out this morning but still can't turn the engine on as of yet. Is the thermostat really necessary? I fail to see its purpose on an outboard, wouldn't we want constant water-flow?

 

[erikpn]

Re: force 120hp overheating

To allow the engine to warm up to proper operating temperature in a reasonable amount of time

 

[john from md]

Re: force 120hp overheating

The engine was designed to run at an optimum temperature. You can run it without the thermostat but you pay for it with the following.

Longer warm up times, and the Force is cold blooded to begin with.
More carbon build up
Less fuel efficiency.

BTW, you need to check your overtemp warning buzzer to see why it didn't go off. Overheating is the primary cause of outboard engine failure.

Regards,

John

 

[TYLER HUNN]

Re: force 120hp overheating

found out my force 90hp was overheating because of a damaged head gasket. you can look at my thread under my name. one thing i now realize about these engines is they are very delicate. you cant really hammer on em for too long without watching for problems.

 

[jerryjerry05]

Re: force 120hp overheating

Running on a hose doesn't always get enough water to the motor.Running it on a hose only sends 1 gal a minute.In the lake you have an unlimited supply.
You should NEVER run an outboard on a hose for more than a few minutes.J

 

[swick]

Re: force 120hp overheating

Thanks for the input guys. I'm going to pull off the lower unit and check he condition of my impeller tomorrow. The starter is toast, I half-fast attempted to get it started today with a rope, I might try one more time, just to see how its running and get it flushed out, but I'm not going to kill myself trying.

Tyler- is there anyway to check the head gasket without pulling the head off? I know in a car you can see if water mixed with oil, not so in the outboard though....

 

[john from md]

Re: force 120hp overheating

There is no sure way to see if the head gasket is torn without removing it. If you don't know the engines history, it will also give you a good look to see if it has been overheated or has excessive carbon build up.

John

 

[swick]

Re: force 120hp overheating

Sure enough the head gasket was done. I replaced it a few days ago. Starter should be here today per UPS, and I just pulled the L/U off to check the impeller; its toast too. The Impeller was worn just enough for me to not know which direction to put the new one on. Any advice?

 

[swick]

Re: force 120hp overheating

I figured out the impeller direction. Its the same as drawn here: http://www.boatpartstore.com/obdrive.asp

Once I took out the impeller and let it sit for a couple minutes it resume its natuaral shape, plus I could tell by the rubber marks.

 

[john from md]

Re: force 120hp overheating

Good time to change the lower oil while you are at it.

John

 

[swick]

Re: force 120hp overheating

Yeah changed the l/u oil a couple weeks ago. I just put everything back together, including the new starter. Nothing. Just getting a click sound for a sec before silence. Could this be the solenoid? I guess there was nothing wrong with the old starter, but the year warranty was almost up anyway. I'm thinking a bad relay wouldn't make a sound but I'm not certain. I'm going o have my wife turn the key while I try and pin-point the sound.

 

[john from md]

Re: force 120hp overheating

Clicking only means that the terminal bar in the solinoid has pulled down. It is usually an indication of a low amperage condition. Before changing parts, you need to check the following.

Have you had your battery checked with a hydrometer or high rate discharge tester?

Have you cleaned the terminals on the battery, solinoid and the engine ground?

Make everything shiny, charge the battery (if it is good) and try it again.

Report back.

John

 

[pnwboat]

Re: force 120hp overheating

Remove and clean all of your battery cable connections, both on the battery itself and on the solenoid and starter. If they all check out, have your battery load tested.

 

[swick]

Re: force 120hp overheating

Thanks guys. The battery is brand new and fully charged. I bought it a few weeks ago along with an onboard charger thats been plugged in since yesterday afternoon. All conncections are extra clean. Its not the relays, I took the relays out of my truck (same size & power) and swapped them in to eliminate that possability. On board charger says the batteries are all fully charged also.

 

[swick]

Re: force 120hp overheating

I'm pretty certain that the solenoid needs to be replaced, not a big deal just another $20-$30. The pbvious answer it to purchase the same one as the one thats on it now, but what I'm wondering is; does it really matter? Isn't one solenoid just as good as the next? This is hypothetical, I'm just thinking, all it really is is a switch.