1986 Force 50hp overheated a few times, now it wont start

jayboonze

Cadet
Joined
Oct 28, 2008
Messages
17
Okay fellas, ive been putting every extra penny I have into this fixer-upper and just when I thought I had it running for atleast this season it proved to me otherwise.

Aside from the engine being 24 years old it was running pretty good. Never had any problems out of it once it started. (the problems I had getting it started were fixed by having the starter rebuilt, replacing the battery cables, and replacing the spark plugs.) But, I messed up a few weeks ago and sucked up some grass covering the water intake. Didnt realize it until the engine was over heated, when I down throttled it died. I pulled the impeller out and luckily it was not damaged. The next time I took it out she ran but several times on acceleration she died, it was like she lost power, the engine just muffled lower slower until it died. I could idol all day, but once I went to accelerate it would die again. Slowly I opened her up and she ran for the rest of the trip. Then this past trip she gave me the same problems not far from launch but again they cleared up and I ran around fishing about an hour. On the last run towards home I opened her up WOT. I looked back and no water output. I leaned over and started down throttle and the engine died. Fearful I had seized it up i didnt even try to start it on the trollling in. Once I got home I inspected the impeller again and it was not ate up at all. I put the water hose up to the pipe running from the impeller housing into the engine and water ran out the water exhaust fine. I tried to start the engine with the lower unit removed and all she would do I spin, no fire.

Here are my questions:

1)What could of caused her to over heat that last trip? I was in salt water, not grass or weeds.

2)What damage could I have caused with the two overheating incidents that the engine will not fire now?

I would appreciate someone taking me under their wing and working throught this with me.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,926
Re: 1986 Force 50hp overheated a few times, now it wont start

First do a compression then a spark test.The impeller if it ran dry is probably bad. Replace it just for GP.Did you suck up any weeds or mud?
No spark,could be it got too hot.Remove the flywheel,check the points(after
the comp /spark test.J
 

jayboonze

Cadet
Joined
Oct 28, 2008
Messages
17
Re: 1986 Force 50hp overheated a few times, now it wont start

Okay compression test turned out right at 50psi on both cylinders.

I dont have an official spark tester so i used the Arc/Jump method with a screw driver in the end of the spark plug wire and the other end about half an inch from engine block, arc was weak and farely eratic on both cylinders.

I pulled the flywheel, neither point looked burned,( if that is what I am looking for), while i had the fly wheel off I ran some light grit sand paper over them.

Still no fire.....
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,926
Re: 1986 Force 50hp overheated a few times, now it wont start

Comp should be closer to 150# not 50.If you got spark even weak that's probably not your problem.
I'd guess a bad head gasket.J
 

jayboonze

Cadet
Joined
Oct 28, 2008
Messages
17
Re: 1986 Force 50hp overheated a few times, now it wont start

Is there anything else I should do or replace while ive got the motor apart replacing the head gasket?
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,926
Re: 1986 Force 50hp overheated a few times, now it wont start

Check for cylinder scoring and a warped head.J
 

Banditz

Petty Officer 2nd Class
Joined
Apr 21, 2010
Messages
168
Re: 1986 Force 50hp overheated a few times, now it wont start

Havin the same damn problem now man. Just remove the head and after cleaning it really well, run some copper rtv to it. Then rebolt it down from middle to outside...torque it down tight, around 240lbs...then she will fire up no problem at all.

Water is getting past th egasket and thats what is causeing her to stop running. Now, all we both need to figure out is why in hell water is not getting to the engine when our pumps are running fine. test yours by wrapping black tape around the splines of the drive shaft...of course with the lower end out...then use a drill with a 15mm socket and with the lower out of gear, turn her over in foward on the drill. If its good, you will see water pumping out of the case fast! Mine hit me in the face...while i was standing!

Good luck...
 

hamburgerman

Petty Officer 2nd Class
Joined
Apr 17, 2006
Messages
102
Re: 1986 Force 50hp overheated a few times, now it wont start

Also take the plug out of the top of the motor and flush it out with a hose you will see if there is any blockage the water should make a 3 foot stream out of that hole
I had same problem changed the impeller did not work till I flushed and replaced the whole water pump housing too that did the trick
 
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