1989 Force 50 Running On One Cylinderish

[retrojeep]

I've been tinkering on my 89 Force 50 and did a single cylinder test by taking off the top plug wire and grounding it and running the motor (yes with water in a tank). It runs perfectly fine on the lower cylinder.
When I swap to running on the upper, it barely fires and I have to kick up the idle on the shifter to get it to run. It does run, but not smoothly like the lower.
I swapped out coils and wires and tried the test again with the same results.
I pulled the flywheel off and checked out the stator and coils and all the wires and magnets seem perfect with no burns etc.
I cleaned off all and every connection with light sand paper and double checked continuity where I could. All checks out.
I got my handy manual and check resistant on the charge coils, coils and anything I could find. All is within specks. I don't have a DVA tester to finish up but from what I can tell everything is up to snuff.
This has a single carb and I'm wondering if there could be a fuel issue to the upper cylinder? I did a compression test and got 145lbs on both cylinders. I swapped plugs from both cylinders as well with no change.
I do get high RPM's with the motor under power, around 5300 with my 11 1/2" prop with no stall, sputter or any other anomalies. So I guess I'm wondering if all is well and it just doesn't like to run on the top cylinder for what ever reason. I did this test when I first got the boat and basically have been using it all Summer with no real problems. I guess now I wonder if I'm losing some power on the top end because of a weak cylinder.
Thoughts? or ideas as to what else I can try?
Thanks!
Retrojeep

 

[Docdoc]

Re: 1989 Force 50 Running On One Cylinderish

Hey Retro,
If you've got 145 psi in both cylinders, then your compression is about like a new motor. You didn't mention what the plugs look like when you pull them. does the top one look different than the bottom one?
Force has a tendency to run dirty and the plugs can foul easily. be sure the plug wire fits firmly on the plug. It could be when you ground the plug to the block you just aren't getting a good enough ground for it to fire at idle. As long as it seems to have plenty of power when you throttle up and doesn't die on you, You might want to leave well enough alone. I'd run it for a while and check that top plug periodically for unusual deposits.

I've been tinkering on my 89 Force 50 and did a single cylinder test by taking off the top plug wire and grounding it and running the motor (yes with water in a tank). It runs perfectly fine on the lower cylinder.
When I swap to running on the upper, it barely fires and I have to kick up the idle on the shifter to get it to run. It does run, but not smoothly like the lower.
I swapped out coils and wires and tried the test again with the same results.
I pulled the flywheel off and checked out the stator and coils and all the wires and magnets seem perfect with no burns etc.
I cleaned off all and every connection with light sand paper and double checked continuity where I could. All checks out.
I got my handy manual and check resistant on the charge coils, coils and anything I could find. All is within specks. I don't have a DVA tester to finish up but from what I can tell everything is up to snuff.
This has a single carb and I'm wondering if there could be a fuel issue to the upper cylinder? I did a compression test and got 145lbs on both cylinders. I swapped plugs from both cylinders as well with no change.
I do get high RPM's with the motor under power, around 5300 with my 11 1/2" prop with no stall, sputter or any other anomalies. So I guess I'm wondering if all is well and it just doesn't like to run on the top cylinder for what ever reason. I did this test when I first got the boat and basically have been using it all Summer with no real problems. I guess now I wonder if I'm losing some power on the top end because of a weak cylinder.
Thoughts? or ideas as to what else I can try?
Thanks!
Retrojeep

 

[retrojeep]

Re: 1989 Force 50 Running On One Cylinderish

The plugs typically are a bit black and wet after each run and I've just got into the habbit of cleaning them up after every trip. I've notice that the lower plug usually looks wetter than the top. When I take the boat out in the sound and with the larger waves lately and I don't usually get to run it at an ideal RPM, so I think that is why it is carbonish. This is a photo of the top plug after one day (6 gallons of fuel) on the water.

I got a carb kit and going to go through that tomorrow, but I don't think there is really an issue. Just want to check it out and see if maybe the float is hanging etc.
I did notice that when I got the boat it had different plugs than what is called out. What was in it when I got it were UL77V, but the book calls out UL18V. Not sure why the other was used or if it was benificial.

Thanks

 

[roscoe]

Re: 1989 Force 50 Running On One Cylinderish

Dump those Champion plugs and put in a surface gap plug.
The NGK BUHX is recommended for your motor.

As for the weak spark issue, swap the plug wires, if you didn't already try it when you swapped the coils.

 

[retrojeep]

Re: 1989 Force 50 Running On One Cylinderish

I can only swap coils not the plug wires since the wires are integrated into the coils. When I switched coils it didn't make a difference to the idle. I'm probably parinoid, but there is a big difference in the two cylinders idles. I wonder if the reed for the upper cylinder is sticking shut a bit at idle.
I've never like Champion plugs and will swap them to the NGK's before the next run.

 

[imported_LakeRunner]

Re: 1989 Force 50 Running On One Cylinderish

Some decarb will clean up the plugs and free up a sticking ring or reed. Your problem sounds more like it something before the coils is not giving you and even spark. I would test the circuits after the starter and before the coils. A service maunal will give you the numbers you should be seeing.

 

[imported_LakeRunner]

Re: 1989 Force 50 Running On One Cylinderish

You can get a good DVM from Radio Shack for around 20 bucks. You will really need it. Advanced Auto also will loan you one for testing. They have a real good tool loaner program.

 

[retrojeep]

Re: 1989 Force 50 Running On One Cylinderish

I have my Fluke and it does a great job except I don't have a DVA adapter. I can only go so far with that. I guess I'll have to get that adapter or see if the tool rental place has one (not likely around here).
I'm almost 100% sure it isn't the coils. I rebuilt the fuel pump and carb today just to get that out of the way and nothing wrong with those, though the fuel pump diaphragm was really saggy.
When I use a timing light on the top cylinder it flashes pretty much continuously, though when it misses it skips a flash. I think it is just weak signal from the CD box, but until I can figure out how to check the voltage from the CD box to the Coil input I won't know for sure. When I pull the top plug and ground it while it's running on only the bottom it has a short blue spark and can only stretch out about 3/8" and it's intermittent (missing out a couple times minute).
When I reverse the process and only run on the top (can only do this if I idle it up to max (not in gear)) the bottom wire will gap almost an inch with lots of snap. Swapping coils and wires around only gives the same results.
I swapped around everything I could think of including reversing the entire wire scheme to trick the CD module.
How much can you check without using a DVA adapter as far as running voltages?
Thanks

 

[imported_LakeRunner]

Re: 1989 Force 50 Running On One Cylinderish

"but until I can figure out how to check the voltage from the CD box to the Coil input I won't know for sure."

If you don't have one, get a service manual or Clymers, that will give you the numbers you should be seeing as well as the correct test and troubleshooting procedures. Check your local library, they may have the Clymers or Seloc for check out or you can copy the pages you need an perform the required checks. An analog Volt meter is sufficent enough to perform most of the test.

 

[retrojeep]

Re: 1989 Force 50 Running On One Cylinderish

I do have a manual, but it calls for a DVA adapter to show an average peak voltage. I'm just going to try with my probe adapter and see what I get.
I'll update when I find out something (or give up!)
Thanks
TF

 

[retrojeep]

Re: 1989 Force 50 Running On One Cylinderish

As far as I can get with my Fluke is resistance test and it all passes. When cranking or checking pulse voltage it jumps around to much to get an accurate reading. I'm going to order the DVA adapter tomorrow and try it again.
It could be just the fuel doesn't carry up to the upper cylinder at idle as much as the lower and so it runs a bit rough.
I'll post results with the DVA when it gets here.
Thanks for your help!
TF

 

[imported_LakeRunner]

Re: 1989 Force 50 Running On One Cylinderish

You may want to do the decarb to help clean up the fuel flow issues. A can or two of Seafoam/Deep creep will probably make a world of difference.

 

[Docdoc]

Re: 1989 Force 50 Running On One Cylinderish

Sounds like you have done about everything you can to resolve fuel issues. That only leaves the spark as the culprit. It could be a weak coil or faulty plug wire up to the top cyllinder. With the type of ignitiion system you have, it is dang nigh impossible to fix that without replacing the entire coil/module assembly. Check real carefully to see if there is anywhere the plug wire could be touching the head or arcing somewhere.

On the de-carb issue, I'd go ahead and do what lakerunner suggests. Seafoam is a great product. I also add Sta-bil every time I put gas in and it helps keep things clean as well as retarding varnish build-up in the carb. Good luck!

 

[retrojeep]

Re: 1989 Force 50 Running On One Cylinderish

The motor was very de-carbed more than once and I also ran some cleaner through the last full tank. I'm sure it is probably the CD module. With the swapping of the coils and wires the problem still stayed on the upper cylinder so the coils are not the culprit.
I have a lead on a good used CD module and will swap it out and try it.
I did pull the reed block and check them out and they were in new specs with no issues. The carb is extremely simple setup and with no issues there.
If the CD swap doesn't pan out, then it has to be the trigger is acting up and has a miss.

 

[retrojeep]

Re: 1989 Force 50 Running On One Cylinderish

Just an update on my CD module replacement. I swapped in the brand new one and set out on a test ride. Seemed a bit better top end, but basically the same issues as before. So I believe it is the way it is. The plugs look identical after a day on the water so I figure they are both at least firing the same on top end.
I did get in contact with a guy at Standard Magneto that actually test and builds these CD modules and he said they basically work or drop off one side or both.
I may double check my recirulating screens and lines for blockages, but I'm sure they are clean like the rest of the motor has been so for.
Enjoy your weekend!

 

[pipestone guy]

Re: 1989 Force 50 Running On One Cylinderish

Hey Retro. Just because the rest of the motor is clean doesnt mean the recirc screen is. I have same motor. Checked my recirc valve last year and it was plugged SOLID with gunk. Cleaned it out and idles much better. Not too hard to get at to clean it. I would suggest giving it a try..

 

[mfo]

Re: 1989 Force 50 Running On One Cylinderish

where is that recirc screen and how do you check it?




thnx mark

 

[retrojeep]

Re: 1989 Force 50 Running On One Cylinderish

Just a note on the spark plug above, I changed to pure synthetic oil on the last couple tanks and my plugs are now spotless! Supposed to rain this weekend here in the NW, so I'll take a poke at the screen and see what it reveals!
When I get to the screen I'll try to take a few photos for the curious.