1989 125 Misses on Fwd only

[jim_b_20653]

My 1989 Force 125 misses under load in fwd gear only. It starts fine, idles fine, backs away from pier in reverse fine. starts missing when in fwd gear. under load its misses and shakes. I first thought it was jumping out of gear, but I replaced a worn shifter cable and have adjusted the shifter which had no effect.

 

[pnwboat]

Re: 1989 125 Misses on Fwd only

Oh that's an easy one.....don't put it in forward! LOL Just kidding!

Need to perform a few basic checks. Sounds like under a load it's breaking down. Need to figure out if it's an ignition or fuel problem but first you should check the compression. Should be around 120 LBS on all four cylinders. If that checks out OK a few things to check out. If you've never done this before, a manual will be very helpful.

Fuel:
1. Make sure carbs are clean and no gunk in carb float bowls. Float level needs to be verified. If any fuel leakage here, then you may need to re-build the carbs. Parts are relatively cheap, about $15 - $18. Pretty simple to do and manual shows how. Also fuel mixture screws should be adjuted correctly. About 1 1/4 to 1 1/2 turns out from lightly seated. NOTE: Does the primer bulb on your fuel line get hard when you pump it up? If not, this is an indication that the float level is set too high or a bad needle valve.

2. Look at the fuel inlet filter/screen on the fuel pump to see if any stuff has clogged it up. If so then there may be some trash in your tank. Inspect the fuel pump rubber diaphram. If it looks stiff or has any holes, it should be replaced. Another relatively cheap part $12.

 

[Frank Acampora]

Re: 1989 125 Misses on Fwd only

If the engine only "shakes" in forward, and if it thumps loudly at this time and if the faster you go the more frequent it becomes, then you really need to disassemble the lower unit and check the condition of the drive dogs on the clutch and forward gear faces. When they get rounded from wear, no amount of adjusting or new cables is going to keep them from bouncing in and out of gear.

The control lever should be snapped smartly into gear to help minimise this type wear.

If the dogs on the forward gear are not too badly worn, as a temporary fix, the clutch can be reversed because the reverse gear is used much less and at slower speeds.

However, the only sure cure is to remove the clutch and forward gear, replace them---big bucks-- or regrind the drive dog faces back to square--much cheaper.

The other alternative is to buy another good used lower unit.

 

[jim_b_20653]

Re: 1989 125 Misses on Fwd only

Thanks for the information. I think you are probably right on with the clutch dogs. I removed the cowlling and watched it closley, and when it "misses" the shift mechanism is moving. I replaced the shift cable and there is still enough slop in the cable to allow this movement. Is this normal ? Sounds like I'll be pulling the lower unit soon.