pooh_b_21632
Seaman Apprentice
- Joined
- Jul 26, 2009
- Messages
- 31
Ok I have a 1990-1994 Force 120hp outboard, I am not sure on the year as the tag plate is gone, previous owner unsure of year as he was not the original owner, and local shop narrowed it down to 1990-1994 from part numbers. Anyway ran great last year when I bought it. Last time we had it out it died in the river 10 feet from the ramp and we coasted in dead battery. It was late in the year so we did not replace the batterys and take it out anymore. This season added seafoam to the gas tank (it had stabil in it over the winter) two new batteries, new plugs, and took it out. Started great at the ramp got about a mile out and it started to get hotter than normal (new impeller last july) so I shut it down to let it cool not wanting to cause any damage, sat for about 1/2 hour and it was horrible to get started cranked and cranked no start, hubby pulled the cowl and adjusted idle screw (we have to start in neutral and dont have a high rev). Still no start. Took about 20 minutes to get it going and would not idle had to put it in gear soon as it started to keep going, got dark so back to the ramp and home. Next time out didnt go far 1/2 a mile or so up the river slight misfiring at higher RPMs but we found a school of fish so we anchored and fished then started the motor up after sitting for several hours fired right up, to the ramp and home. Read lots of forums about the rough running and misfiring and talked to lots of people and I was lead in the direction of the ethanol deteriorating the lines and sucking shut. So we changed the fuel lines, primer bulb, and new fuel/water separator. Back on the river running better ran about 3 miles down the river and went down towards idle, motor died gas coming out the carb butterflys would not start and my brother in law had to tow us in. So we rebuild both carbs needle jet was stuck on one thus the flooding out the butterfly figured we had it fixed filled a bucket in the yard to run it the yard and would not fire, lean sneeze/cold sneeze but could not get it to start, but starts on the muffs with a slight misfire even at idle. back to the forums/local people and rebuild the fuel pump starving for fuel thus the misfire. Runs good on the muffs starts fine but still with the misfire. Decided to do a compression test (never had a problem before). #1-135, #2-125, #3-25, #4-125. Tried to fog the third cylinder for a wet test and got 50 then the starter died, replace the starter and retest got 50 so Im like whats up with this thats not enough of a difference to think its stuck rings but maybe, so I read some more talk some more and we decide to pull the head and see whats going on. #3 looks like #'s 1 and 2 slightly dinged like something broke off somewhere and came through there then out the exhaust, and #4 has very very mild pitting like a melted piston from a bad head gasket starting, but it has good compression so I am leaving that alone for now. Anyway the cylinders on all four pistons look pretty great you can still see cross hatches no scratches or any other marks so I am thinking maybe the small dents are old and the engine has been rebuild not that long ago with the same pistons maybe, the rings dont appear to be stuck if you spin the engine until the #3 piston ring is at the exhaust port you can move it with a pick. So we decarbed the heck out of it though all four cylinders looked pretty good. New head gasket torqued it down fires on the muffs still has a misfire will not start in water and were thinking ok maybe the reeds (looks like something got dinged up on the pistons/head breifly) but decided to try spraying seafoam through the carbs for a decarb after about an hour of smoking up the neighborhood recheck compresion and #3 is up to 60 but weve still got a mis. Good spark, new plugs, still low compression (BTW the low compression cylinder is the one that the mechanical fuel pump is on so I think if I can fix the compression the mis will go away). So I figure before shelling big bucks lets pull the reed blocks, they look new nothing broke, chipped or bent, hold it too the light and you cant see past the fingers all is tight none are stuck. I spun the flywheel by hand and hubby inspected the crankshaft nothing there either, So I am still stuck with low compression and no answer. Going to parts store tomorrow to find a fitting for the sparkplug hole for hubbys vaccum guage to see if it leaks at the rings (gonna spin the motor to bring the piston past the ports and pull a vaccum if the rings are bad it wont hold a vaccum, right?) anyway does anyone have any suggestions before I take it to a shop? I like the motor it has been well maintained since my friend got it looks great inside and out very clean and I have maintained it the same since buying it from him I hate to buy another outboard that could have the same problems if I can fix mine for less than a grand. Sorry for the long post but Im lost here. 
