puzzled why wont start

[rsw21282]

i have an 85hp 88-89 force motor, i had this thing running at my house yesterday and took it to the boat ramp and wouldnt start, i have also had problems with when it did start it would only go about 1/4 throttle anymore would die pretty quick. i have checked for spark, all three cyl. have good spark(checked this visually by cranking motor holding plug against motor), i cleaned under the flywheel(before checked for spark), replaced fuel pump diaphragm, have taken apart the carbs 3 times and they seem fine every time. the main air bleed(im guessing thats what it is, brass fitting on the side) is a .050 size, i am at sea level or darn close. Is this size correct? im about on the virge of taking it to a mech. the plugs have fuel on them when pulled so getting fuel, spark is good, and air is an obvious, this equation should equal fire so im confused and how could it break between house and boat ramp? i do choke the motor and prime when i attempt to start, and the inline fuel filter and carb bowls have fuel in them. I also adjusted the carb idle screw out 1.5 turns out after seated and that ran a bit fast so turned it in to 1 turn out after seated and still a bit fast but that is the point when i ran it at house last then took it to the boat ramp where didnt work, is this setting correct? all the "reed valves" look fine, i assume this by looking in the housing after the carbs and nothing seems out of the ordinary, all valves look straight and new. could the timing be off? if so how would i adjust this? i am wide open for suggestions as i am on the last leg of attempting to fix this thing it has been nothing but problems.

 

[kandil]

Re: puzzled why wont start

I would check the kill SW and the comparison

 

[eurolarva]

Re: puzzled why wont start

Check compression and or look at your spark plug tips. If you are running it at home on muffs you do not have the same pressure as when the motor is in the water.

 

[Drunken mechanic]

Re: puzzled why wont start

My experience has been that most of the motors that i have worked on that wont run past 2000 rpm it is a switchbox. To find this out you would have to have a dva meater ran on the box @ the triger.

 

[rsw21282]

Re: puzzled why wont start

compression is the only thing i havent checked, but it should still fire right?just run rough. the prob is with the water drag theory, is now it wont even run on the hose. the trigger thing, is there anyway i can test myself(without specialty tools, other than a multimeter)? shouldnt i still have some backfiring or something with timing off to? i have never worked with a surface gap spark plug, the spark is just a small one like on a norm plug should it be anything fancy or larger? just throwing random stuff out now since i am puzzled.((runs at home fine, gets trimmed up and trailered 15mi and now doesnt run, whats the problem?))puzzled

 

[Silvertip]

Re: puzzled why wont start

If you mucked with the idle "mixture" screws, that could be part of the problem. Those are idle mixture adjustments not idle speed adjustments. There is no final setting for them, just an initial setting of 1-1/2 turns out from lightly seated. The final adjustments are to made with the engine in the water, not on muffs -- again due to back pressure differences. A compression check is in order but I suspect you have an ignition issue. Surface gap plugs can be very unforgiving with weak spark even if it appears spark appears to be good. Put some new plugs in it and try it. Engine timing is part of what's called the Link & Sync procedure which synchronizes throttle settings with ignition timing. That procedure is far too long to post here and requires a service manual specific to your engine. That procedure must be followed to the letter from beginning to end. Screwing with anything in a random manner only makes things worse. Although you may have had the carbs apart, have you actually rebuilt them -- as in soaked in carb cleaner (except for plastic parts), made all internal passages squeaky clean, blown out with compressed air, and then reassembled with new kits. Adjusted float level properly?

 

[rsw21282]

Re: puzzled why wont start

all the plugs are new, the spark is a bit faint looking to me again tho i have never delt with surface gap spark plugs and am not the most knowledgable about 2 strokes or marine engines. i am starting to think the cd boxes are bad but im taking it to a mech. i dont know how to check them and they are to expensive to order on a hunch. the carbs are clean, i sprayed wd-40 through every orfice in that thing and it is squeeky clean, and like i said i have fuel on the plugs so something if only a backfire or something should happen right? this is an old boat and had some funky wiring in it, i had an old,old kill switch wired in the ignition and it was stuffed in a hole down the line so it would kill it sometimes others it wouldnt, anyway i wonder if this or me testing the ignition by disconnecting the two white wires that short the cd boxes to ground when the ignition is off, to test for a problem may have caused an internal problem in the cd boxes? unless anyone has any suggestions for me ill post the result of the problem after i get it back. i am still wide open for suggestions!