1985 85hp Force engine - thermastat?

[dodge69]

I have a 1985 85hp Force engine. Where is the thermastat located at? I saw in another blog where a person changed out the thermastat due to corrossion and now engine runs fine.

 

[jerryjerry05]

Re: 1985 85hp Force engine - thermastat?

It's located at the top of the powerhead.Rectangular box,4 screws.
What's wrong with it that you need to fix something?Is it overheating?
With an outboard at the first sign of trouble do a compression test then a spark check. Jerry

 

[dodge69]

Re: 1985 85hp Force engine - thermastat?

Yes it is overheating. We found that the exhaust hose was bad and replaced it but motor still doesnt run good. The motor runs great at low speed but when you give it gas it bogs down and sometimes dies. What is weird is the motor will not fire over while it is down in the water. I have to manually pull the engine up and have someone else turn the motor over, then I lower the motor back down. I have hooked the motor up to the water hose here at the house and it will crank over everytime but no water ever comes out of the power flow tubes.

 

[eurolarva]

Re: 1985 85hp Force engine - thermastat?

Yes it is overheating. We found that the exhaust hose was bad and replaced it but motor still doesnt run good. The motor runs great at low speed but when you give it gas it bogs down and sometimes dies. What is weird is the motor will not fire over while it is down in the water. I have to manually pull the engine up and have someone else turn the motor over, then I lower the motor back down. I have hooked the motor up to the water hose here at the house and it will crank over everytime but no water ever comes out of the power flow tubes.

This says you have a cylinder that is not firing. When you overheated you possibly damaged a cylinder. As mentioned by jerry you need to do a compression and spark test before you go any farther. When you use water muffs there is no back pressure and motor will start and sound fine with a cylinder not firing. When you put the motor in the lake the back pressure is too much and the motor will not start.

 

[dodge69]

Re: 1985 85hp Force engine - thermastat?

Ok, this is my first boat so don't know much about all of this. So how and what do I need, to do a compression test?

 

[puddle jumper]

Re: 1985 85hp Force engine - thermastat?

What i would recommend you do is get a friend who has the tools to do a compression test and show you. A compression tester is a gage that you screw into your spark plug hole and it reads the amount of pressure that the cylinder makes when the engine is cranked over at starter speed. Most engines will make about 150-120 pounds pressure per cylinder. Any thing below 100 pounds of pressure is considered a dead hole. Hope this helps.

 

[eurolarva]

Re: 1985 85hp Force engine - thermastat?

tester can be purchased through Sears or most auto parts stores for 30 dollars. There are a few things you need to know or you can do damage to the electrical system and the piston. First you need to pull all the plugs out. You need to ground out all the spark plug wires. Then you need to insert a piece of soft wood like a Popsicle stick and turn the flywheel clock wise till the stick comes all a way out this is Top Dead Center (TDC). Some compression testers have extensions on them that will go too far into the cylinder and the piston can smash into it. Now you just screw the tester in till tight and crank the starter three times on each cylinder and write down the highest reading on each cylinder. Normally this is done on a warm engine with the throttle wide open. Warm engine would be ideal but the wide open throttle makes little difference.

When you remove the spark plugs look at the tips. A clean one is usually the problem cylinder. Count 1 as the top cylinder and then count down to 4 being the lowest cylinder or 3 depending on your motor.