Low speed only

[398260]

I have a 1996 Force 50 Horsepower. It started running at low speed only, no matter if you give full throttle. It runs super smooth, but only at low speed. I have replaced the two coils, checked every thing I can think of that might indicate a fuel issue. but no luck. When I try squirting gas into the carburetor while at full throttle, it wants to choke out. Also, it dies a lot when idling, even though I have tried to adjust it up - but didn't know how to adjust the throttle cable to match. Could this be part of the problem? Someone suggested stator...............anyone else ever have this problem? Also, it will randomly kick in and run right for short periods of time, which leads me to believe a broken or partially broken wire somewhere perhaps.

 

[legalfee]

Check out the CDI trouble shooting guide. My 1995 Force 90hp would not crank. Replaced the power pack still would not crank. Replaced the trigger and stator. It cranked stator was bad. It ran but would not go full throttle disconnected the regulator / rectifier and got WOT. Replaced RR. When the motor got hot it ran rough and cut off. Replaced coils. Ran smooth. One recommendation is don't buy cheap RRs. Get a CDI. My tach didn't work with the cheap RRs. My thinking is it won't hurt to change out all the ignition parts on a 23 year old motor.

 

[roscoe]

First things first, before you replace any more parts.

Check compression on both cylinders.
Check for spark on both cylinders.

Run the engine for a 5 minutes, then check the sparkplugs for condition, color, wetness, carbon build up.

 

[398260]

Thanks, I will check the compression and spark.

 

[Jiggz]

One quick and easy troubleshooting you can do is, "drop cylinder" test. Do this, while idling, pull off one plug cable at a time and listen for changes in engine rpm sound or tune. Or if it even stays idling. If there is no change in engine rpm or sound, that means that particular cylinder is not firing. If the engine dies, then that cylinder is probably the only one firing.

 

[legalfee]

WILL NOT ACCELERATE BEYOND 3000-4000 RPM: 1. Disconnect the Yellow wires from the stator to the rectifier and retest. If the engine now has good spark, replace the rectifier. 2. Connect a DVA meter between the stator’s Blue and Blue/White wires. Run the engine up to the RPM where the problem is occurring. DVA voltage should increase with RPM. A sharp drop in DVA right before the problem occurs usually indicates a bad stator. (Read from Blue to engine ground if the engine has a Red stator kit installed). 3. Connect a DVA meter between the stator’s Red and Red/White wires. The DVA voltage should show a smooth climb in voltage and remain high through the RPM range. A reading lower than on the Blue wire reading indicates a bad stator. 4. Connect an inductive tachometer to each cylinder in turn and try to isolate the problem. A single cylinder dropping spark will likely be a bad switch box or ignition coil. All cylinders not sparking properly usually indicates a bad stator. 5. Perform a high-speed shutdown and read the spark plugs. Check for water. A crack in the block can cause a miss at high speed when the water pressure gets high, but a normal shutdown will mask the problem. 6. Check the triggering and charge coil flywheel magnets for cracked, broken and loose magnets.

 

[398260]

Thanks for the tips. Gives me something to go on.

 

[jerryjerry05]

Do as Roscoe and Jiggz suggested.
Don't buy anything yet.
These 2 cyl. motors run pretty good on just one cyl.
outboardignitiondotcom has test procedures for the electrical system.

Drop the bowl on the carb and check for gunk.
The primer system can go bad and allow excess fuel into the motor.
Pinch off the lead to the bottom of the carb.

The fuel pump diaphragm can also do the same.
Check it.

 

[398260]

Thanks for all the help folks! I went home last night and decided to do a meticulous search of the wiring to see if I could find a broken, or partially broken wire somewhere, and also did a drop cylinder check and found that only one cylinder was firing...........after a flashlight inspection, I found what I was looking for. In the wire bundle coming out from the bottom of the stator, where you can't see very easily from a quick glance, one of the large yellow wires was almost completely rubbed into, with only a couple of the copper strands just barely making contact......I think this might explain why it would randomly kick in and run good for a short period of time. One of the other wires had completely rubbed through the insulation as well. I lacked the proper connectors to effect the repair, so I will pick up some today and see if that fixes the problem. Fingers crossed!

 

[Redbarron%%]

A quick check is to use your timing light to check for fire on each cylinder.
I had a similar problem with a three cylinder 90 hp Sport Jet and the trigger to the #3 cylinder was breaking down and not firing.
Showed up easily and quickly with the timing light test.

 

[398260]

Thanks Redbarron. Hoping fixing the broken wire will do the trick.

 

[398260]

Repaired the broken yellow wire coming from the Stator...........now both cylinders are firing and she's running like a champ!

 

[Jiggz]

Great and congrats. Enjoy.