Force\gamefisher 9.9 thermostat??

littlefish

Cadet
Joined
Oct 13, 2004
Messages
6
This is probably a dumb question, but is there suppose to be a thermostat on a 1988 9.9hp force? I'm replacing the water pump and wanted to make sure everything else was working. I don't see any thermostat's mentioned in the various schematics available on the web. I've only run this motor once for a short time and it seemed to run very hot, thus the water pump replacement. The old pump actually didn't look too bad. The water passage in the power head seems clear too (can blow air through). Any help\advise is appreciated! Thanks!
 

FlyBoyMark

Ensign
Joined
Apr 14, 2002
Messages
934
Re: Force\gamefisher 9.9 thermostat??

Nope..none..BUT...you could be running slightly lean or your spark advance is out of whack. The spark advance on these particular engines is easy to mess up if you fiddle with the linkages on the carb. In addition there is a very tiny fuel filter/screen on the inlet side of the fuel pump(bottom and looks like a nert fitting). Unscrew and look for crud, also replace pump diaphrams and seals, that puppy is getting a little old. Make sure you are using the proper spark plugs and last but not least, the carb is very finicky about crust in it. Dissassemble and clean VERY carefully all the jets and little passages. The primer button on the front of the engine has a little bulb under it that is prone to cracking and leaking. Check that item and the little hose that attaches it to the carburator for air leaks. Decarbon job afterward should help too. These actions should reduce the hot running problem your having. Make sure your running 50:1 premix with a good quality TCW-II or TCW-III oil...<br /> As a last thought.....are you lugging the engine mounted on a "slug"? 600-700 lb. load is all most 9.9 will push without going to a lower pitch "push prop". :cool:
 

littlefish

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Joined
Oct 13, 2004
Messages
6
Re: Force\gamefisher 9.9 thermostat??

Thanks for the info. I was thinking that there could be air leaking in at one or more of the various fuel lines. Someone recently did a carb job (looks new) but missed a few fuel line clamps. Maybe they messed up the spark advance too... I just ordered new plugs and plan to de-carb this weekend. Is there any kind of timeing mark or easy way to verify the spark advance is correct or working?
 

FlyBoyMark

Ensign
Joined
Apr 14, 2002
Messages
934
Re: Force\gamefisher 9.9 thermostat??

There are no clamps on the primer line BUT the hose must be plyable and fit snuggly on the carb and primer bulb/button, again, make sure that this bulb assembly is not leaking air. The spark advance linkage is basicly FIXED, but the carb can be adjusted. It should be fully open before full advance. There is a little black roller on top of the carb that is mounted on a nylon moulding that is hinged and has a little adjustable wire(this is what people mess up) going down to the carb butterfly. This little black roller should almost be touching the spark advance cam plate with the throttle grip fully retarded. as you turn the throttle grip and the black roller hits the bump in the spark advance cam plate, the carb butterfly should be fully open. There is additonal travel after this point but it is only in the form of spark advance for the balance of power. There is some adjustment on the spark advance but it requires bending of the linkage.<br /> If all of the above is ok... <br />If you are advancing the throttle to a point and the power gain stops with further increase in throttle setting, you have a lean condition and it must be cured before destroying your engine.<br />One last thought...check your fuel line fittings and hose for air leaks, make sure tank is vented..AND did you insert the water tube in the leg properly when you put the lower unit back on? Was it damaged earlier from a previously improperly installed lower unit?
 

littlefish

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Joined
Oct 13, 2004
Messages
6
Re: Force\gamefisher 9.9 thermostat??

The water tube looked fine and the lower went back together with no problems. The spark advance and carb butterfly appear to work as you describe. I'll let you know how it runs after the de-carbon run. Still ned to find some fuel line clips. Thanks for the excellent info!!
 

littlefish

Cadet
Joined
Oct 13, 2004
Messages
6
Re: Force\gamefisher 9.9 thermostat??

Update: Motor runs good now! New water pump, new tie-locks on the carb fuel lines, de-carbed motor, new plugs and newly bought Chevron supreme gas. Runs cool now and idles well. Timing seems OK, but I've have not run this motor full out on a boat yet. Only been testing in a barrel. Now I need to re-build the cowling with fiber glass. Back section broken out bad and a new one would cost $126... Thanks for the help!
 
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