1990 force 50 stalls, misfires,very hard to start when hot?

Just bought a sweetwater pontoonboat with 50 HP Force. Previous owner admitted to cooking the water impeller when he ran it in his yard-He had reciepts for the new water impeller, but managed to set off the alarm during test run with Muffs on a hose for cooling while I was there! Starting was a real pain when it was cold, neary impossible when it was hot, and it would stall out and misfire constantly!This is my third boat with a Force motor, my other two were absolute blessings with nearly 15 years of trouble free and smooth performance.Yeah, I ve got a real basket case but I think this Forum is a good place to start, No ,Im not going to give up and use it as an anchor! Hope to be cruising the lake with smooth reliable performance after meticulous attention to detail and some good technical advise!I read post all day yesterday, joined three forums, tapped into e-bay for parts and manuals- so time to roll up my sleeves and get busy! Ill keep you posted!

I see you did start your own. First thing start with a compression test. Post the results. If it's been that hot more than once it could have some damage in the piston area.

thanks jerry, still havent brought the boat home yet- got to get the trailer and boat legal for the drive back! Get it home i can really get busy!

Got my plates and stickers, its legal!!!!!!!!!!!!!Ill be into it real soon! love force motors!!!!!!!!!!!!

Well, today was the fist day to really take a look at her , she only started once and ran terrible and overheated! So I decided to pull the bowl off to see if she was clean inside but she was filled with sediment! took off the carb and cleared her out best i could, Put it back togethrt and she ran sweet with no skippin! Checked the heads and she seemed hot? leg and lowere unit were nice and cool? Think i might have a thermostat problem! Wouldnt start hot after a few tries? Ill try finding and removing the thermostat and sees if it stays cool! Pretty happy so far!

Anyone know how to clean the filter? Iknow the card was nastey so the filter is probably much worse!

By the way,The starter motor has real nasty teeth and was spinning even after the motor started? Then the enginr kept running even after i turned off the ignition and took out the key! Notice engine rpms got noticably higher as the enginge got hotter and hotter? This motor seems to need an Exorcist!Definetly a unique and entertaining afternoon!

The 50 needs a special muff or a very deep bucket.You need to have the water deep enough to be 2-3 inches over the cavitation plate. Change the impeller before you do any real damage.You do a compression test? Starter running on is usully the key switch or the solenoid. Not shutting off is usually the ignition switch. Sometimes spraying WD-40 in the switch will help. You can get a new bendix/gear for the starter, is the flywheel chewed up? Outboard ignition . com has test procedures for the running after the keys switched off.

thanks jerry, I took the thermostat out and it was pathetic toast! never seen a thermostat look so roasted and broken!The impeller must also be toast because no mater how deep the water is it still wont cool the heads even without the thermostat! The starter was running full speed even with no key! although it did not extend to engage with the flywheel, even with the ignition key off and out the only way to stop it was disconnect the battery! Had to turn key off and on again before connecting battery was possible . Yikes!

hey, im looking at compression gauges, craftsman-#$75.00 or acutron for $30-45 ? any suggestions?

I just walked out to my boat and my engine started screaming in Latin, spun its head around several times and threw up green nasty vomit as i aproached the transom! After stabbing itself in the crotch several times with a crucifex it began to rise slowly off the ground!!!!!!!! Its still about 5 to 6 feet off the ground but im just going to ignore it till tommorow!Ill try some carburetor cleaner and see what happens!

Sounds like it has formed an alergic reaction to YOU!!! Any guage is better than none. A cheap one might work or give you cheap results?? I paid about $100 in 1985 and it still works better than any other. Does the whole key switch move when you try turning the key? Sounds like a bad connection somewhere? The solenoid might have gone bad too.Test light across the poles when the key's off.

Thanks for the laugh Jerry! I needed one yesterday-I think a new starter motor,Rebuilt carb, and waterpump kit and thermostat should give me a huge shot at eliminating the big issues Im now facing, the fact that it usually runs without a skip after i cleaned all the sediment from the carb and jets tells me the major ignition electronics are probably ok. I do suspect the key or solenoid or related wiring may need some closer examination.The key assembly doesnt seem to turn or show other signs of outward defect- Again, I do need to take a closer look tommorow-by the way, since cleaning the carb Ive noticed at least twice the power, probably far more actually than when i bought it, it was surely starved for fuel.Thanks so much for your insight jerry! ive never ordered parts online for a boat motor-Ive found model and serial numbers on the Starter housing that match the ones on the transom mount, is that the engine serial # also?

Well, Im 54 years old and been working on cars truck boats ect since i was 15- for the first time ever, a vehicle i had worked on for several hours meticulusly cleaning and assembling actually went up in smoke! started my new starter motor and watched with great pride as it work flawlessly at spining my old motor- was just about to purchase a compression gauge thinking my lower cyclinder was pathetic and barley put any pressure against my thumb when i tested it? one last look at my pretty new starter in action when fire broke out and fried my wires, hoses plastics, ect! fuel line apparently cracked and the rest is history! motor is toast for sure! what a terrible end to so much effort and time on this engine!

Well Chuck, I think you should buy a nice 100 hp Johnson Commercial motor for that nice little pontoon boat! put the force motor on a mount in your garage. Then, rebuild it ,pistons and all, over the winter! Make a nice secound motor to have on hand!

The fire usually's started by a loose connection. Sorry you'r having so much trouble. I've never seen one with so many problems.