Need Help With Force Motor

[pnwboat]

Re: Need Help With Force Motor

Remove the plugs, but leave them attached to the plug wires. Take four lengths of wire and wrap it around the threaded portion of each plug. Take the loose ends of the 4 wires and attach them to the block. Take a piece of electrical tape or a tie wrap and wrap around the neutral safety switch to hold the little white button down. Set your throttle WOT. Attach the timing light to #1 plug wire. Use you key and crank the motor over and observe the timing mark. It should be set at 28 to 30 degrees.

 

[PaulO]

Re: Need Help With Force Motor

I made the same mistake with the sealant and those four bolts. It was bloody hard getting the motor up there on the leg then I had to take it off again. I got help the second time

In cranking mode set the timing to 28? for 1990-1991C Prestolite Magneto CDI
32? for 1991D-1995 Thunderbolt CDI

It is just a matter of adjusting the screw that is connected between the throttle tower and the trigger. Loosen the lock nut first.

Make a note of the current timing angle and report back.

Mine was set >40? which caused pre-ignition and detonation melting the head of #4 piston and stuffing the bore, prior to acquisition. She is all good now.

 

[brianvolt7]

Re: Need Help With Force Motor

The timing is way out. I hooked the light to the number one sparky and it apears to be at around 16 degrees. It is right between TDC and the first mark which according to a previous post is 28.

I don't think an exact timing can be found on this motor becaus the guy that sold it to me said the block is out of an 89 125 or 120 but was not sure.

I went with pnwboat's general recommendation of 28-30. I set it slightly closer to the 30 so its probably 29 1/2, this was between the mark in the middle and the mark to the right of that. Is this correct?

Does anyone think I will have problems with this?

 

[brianvolt7]

Re: Need Help With Force Motor

I took the oportunity to compression test the block. Of course the range of 150 promised by thet seller was not what I had.

Here is what I have:

1= 120
2= 121
3= 119
4= 114 ??????



Is the 114 OK? I have a brand new head gasket that I can install next weekend, do you think this would help? Am I looking at a total rebuild?

 

[pnwboat]

Re: Need Help With Force Motor

Your timing should be close enough for the time being. It should be set at 28 degrees for the Prestolite system per factory specs. I've run mine at 30 degrees for many years with no problems. I do use 89 octane or higher though.

Those compression numbers are on the low side but still acceptable. Different compression gauges will read differently. Most important thing is that they're all pretty much the same. 6LB difference between highest and lowest is a good sign. At this point I would run it as is and enjoy the summer.

Your only issue now is the overheating. I wonder if the timing being retarded by 12 degrees could cause it to overheat??

 

[brianvolt7]

Re: Need Help With Force Motor

Well, I will find out tomorrow. I just filled the tank with 91 octane and a 50:1 mix.

When I return on Thursday I will let everyone know how it did.

 

[PaulO]

Re: Need Help With Force Motor

Just to confirm:

Were the two throttle valves horizontal (equal )when you checked the timing? If they were not the timing angle will exceed 30? when they do sit horizontal.

 

[brianvolt7]

Re: Need Help With Force Motor

Boat on water report:

WAHOO! Tubing, fishing and cruising. No overheating.

She was a little slow to get on plane but it?s a 20 foot cuddy cabin so I have always had that problem. I had a trolling plate on instead of the planing fin which was likely the biggest problem.

It trolled down perfectly and I caught 2 brown trout on Wednesday morning, one 15 and one 16. Nice fish, great with butter and pepper

Pulled my wife and daughter on the tube at idle for 20 minutes and then my wife a couple of times at plane and ran great.

Ran like a top!

The only glitch was after high speed plane or low speed trolling if I put it into neutral for a minute it idled perfect but it would die when popped back into gear (reverse or forward). I would then have to start it and put into gear and throttle up real quick and then back down to idle to keep it running. It would not do this at the dock though when cold, I could pop into reverse or forward at idle speed and idle right out. Could this be fuel supply or timing being at 29 1/2 instead of 28?

The blades in the carbs looked open at the same angle when timing was set.

 

[PaulO]

Re: Need Help With Force Motor

Timing sounds Ok. When at idle the timing is approx 4? ATDC and RPM increase is only achieved by advancing the timing but not opening the throttle valves.

It might be worth a try leaving the engine cover off and try putting it into gear. If it doesn't stall it may be exhaust gases leaking past that lower seal and starving the engine of oxygen?

or

there is a fuel supply issue. Where do you start??

 

[pnwboat]

Re: Need Help With Force Motor

Or could be idle mixture a little too lean. Adjust 1/4 of a turn out and see if that makes any difference.


Great to finally hear some positive news!

 

[brianvolt7]

Re: Need Help With Force Motor

I will try these ideas next time I am on the water. I think that will be next weekend.

 

[PaulO]

Re: Need Help With Force Motor

Any updates Brian?

 

[brianvolt7]

Re: Need Help With Force Motor

No updates- I have been so busy on the weekends I haven't had it out. I am planning a fishing trip to the Delta by Sacramento in a couple of weeks. Going after Stripers and Catfish. This will be it until the salmon come in to teh Sacramento River (after hunting season). Right now I am tuning the quad up for the season opener in mid September.

I will let everyone know after my Delta trip.

 

[brianvolt7]

Re: Need Help With Force Motor

This has me confused. I took it to the lake the last night to do a little trolling. I started it at home first and it had a super high idle. I adjusted it down a little and it ran fine. Here is what happend at the lake:
1. started up fine, no problems at all
2. put in gear, died instantly
3. had to put in gear and throttle up fast the rest of the day to get moving
4. on plane, it ran perfect
5. the motor would troll for about 1 minute and then die, like it was running out of gas

I think I did something I should not have. I poored oil into the tank then put 10 gallons of gas in, I did not pre-mix. Could this have caused the problems above. Also the motor was smoking bad each time I started it up.

I did find that there is exhaust leaking into the motor compartment from the lower leg as well.

The good news- I brought home 3 nice trout caught while anchored and 5 fat crawdads.