1993 mariner 40 hp, idles great, no power

[ggrundel]

I have a 1993 mariner 40 hp, 4 cyl, 2 stroke, electric start, s/n 0D237386.

Was running down the lake at 26 mph, ran out of gas, switched gas tanks and had a hard time starting. finally started and wouldn't go above 12 mph. I went through the whole fuel system - new gas, replaced fuel pump and filter, cleaned carbs. Starts and idles great now. but when I throttle up I can't get it above 7 mph.

At idle with muffs, I pulled number 1 spark plug wire. No change in engine, even though it idles great. Put 1 back on and pulled 2, still no change. put it back on and pulled 3, it died. put it back on and pulled 4, it died.

I used a spark tester and getting spark from all 4 coil packs, which is weird considering no change in engine when pulling the wires. I also did a compression check and all four cylinders reading 115 to 120 psi.

Not sure what to test next, any suggestions?

 

[Texasmark]

Well that says to me that you are running on 2 cylinders. Upper carb is either clogged internally, needle valve and float setup not setup properly, or you don't have the low speed adjustment screw set right.

With no load like on muffs, a multi cylinder engine will seem to run just fine on half of the cylinders.

Mark

 

[ggrundel]

I'm getting fuel. I purchased a DVA adapter and tested my switchbox. 3 and 4 are getting 185+/-, but 1 and 2 are only getting 13+/-. From what I have read, that tells me it is the stator or trigger, but not sure how to tell which. I have visually inspected my stator and I see no burns or anything that looks damaged. is there a way to test the trigger without removing it?

I re-installed everything to be able to run the motor to use the DVA tester. Not sure if I have to just visually inspec trigger or test some other way.