Purpose of Trigger ???

Jasper8301

Cadet
Joined
Oct 22, 2009
Messages
23
I have a 1991 120Hp L-drive that won't fire on #1 & #2 intil about 4000 rpm, is this normal? Any info on timing would be greatly appreciated<<<Thanks
 

pnwboat

Rear Admiral
Joined
Oct 8, 2007
Messages
4,251
Re: Purpose of Trigger ???

Sounds like maybe a stator problem. Here is a chart that shows what readings you should be getting with an OHM meter.


http://www.cdielectronics.com/downloads/Force_DVA.pdf


NOTE: Looks like in 1991, there is a stator that had a separate low speed winding and high speed winding. This may be why you see spark only at high speeds. Bad low speed winding??
 

Jasper8301

Cadet
Joined
Oct 22, 2009
Messages
23
Re: Purpose of Trigger ???

I replaced the switchbox yesterday and still have the same isssue,,,, cleaned the stator also and switched coils,,,,
 

pnwboat

Rear Admiral
Joined
Oct 8, 2007
Messages
4,251
Re: Purpose of Trigger ???

Sorry Jasper, I edited my initial response while you were replying. Exit the forum and come back in to see my update.
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,753
Re: Purpose of Trigger ???

The purpose of the trigger - tells the spark when to fire.
 

Jasper8301

Cadet
Joined
Oct 22, 2009
Messages
23
Re: Purpose of Trigger ???

ok. I replaced everthing,,,stator ,trigger, switchbox and rectifire,,,,runs on all for at idle but idle timming is at 10 btdc,,, I adjusted the sync licaged all the way in amd out and did not change the timing at all. Can you rotate the stator and change timing or is the stator just for charging only or does it help the trigger fire ???? help...thanks
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,074
Re: Purpose of Trigger ???

Timing needs to be done at WOT,You need to get a manual if your gonna try to time it.J
 

Jasper8301

Cadet
Joined
Oct 22, 2009
Messages
23
Re: Purpose of Trigger ???

ok, thanks to all...I've got it static timed to 28 Deg,, and it fired right up,,but now it idles at 3500,,,what next ? is this an idle screw adj.issue or timing still out ? should I take it to the lake and leave it on the trailer and put it gear to adjust idle screw?
 

pnwboat

Rear Admiral
Joined
Oct 8, 2007
Messages
4,251
Re: Purpose of Trigger ???

Make sure the carbs are properly sync'd. Idle mixture screws on carbs should be in the neighborhood of 1 to 1 1/2 out from lightly seated.

There should be a line or mark on the throttle cam attached to the bottom carb. It should more or less line up with the roller on the carb throttle shaft at idle. If it doesn't, proceed to the steps below.

There is a mechanical idle adjustment on the vertical tower shaft. It has a lock nut to keep it from turning once set. The yellow line in the pic below points to it.

Also there is a rod with two plastic snap connectors that are threaded onto the rod. (Look just above the yellow line in pic) It connects between the vertical tower shaft and the throttle cam on the bottom carburetor. If someone has messed with the two plastic connectors and loosened them, essentially making the rod too long, it will hold the throttle plates open too much.
 

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