[kessun]

Hey guys, I opened up a new thread to make thing more clear and hope that get somewhere with my sled.

previously I had some flooding issues, from carb cause was old fuel, water in the system, needle and seat malfunction, poor calibration on carb.
if someone has issue getting too much fuel I'd get into that first.

now that I have perfectly working carb, clean fuel tank and new fuel lines vaccum lines factory set carbs my sled won't start.

when the sled was flooding out to lunch, it would fill up to exhuast under 5 min, it started at first pull but very poorly.

my compression sits around 145 on both cynlinders when I test the plug (I ground it on the head bolt then pull for spark) it will show blue spark in good consistency and at pilot jet #50 air screw 2¼ turn out (factory setting for both summit 670 (#75) and formula ss (#50) I just have HAC delete) fuel is coming out good even with mixed gas poured in cylinder nothing happens.

I have two nipple to crank case one for fuel pump other for fuel overflow I guess but it was plugged. I used both nipple to suck the fuels out. still small amount of fuel sprays out from nipple but cynlinders doesn't spray any fuel or oil into my spark plug

carb is spotlessly cleaned, no gunk in any fuel system, 91 fresh fuel, no more flooding unless I give too much primer

I let it sit with spark plug pulled out pecock turned off in 5 degree celcious warm shop with vent overnight, I pulled exhaust out and gave it a pull and it started right up first pull, going strong sounds healthy, so I shut it off cleaned out the exhaust put it all back gave it a try, nothing happens.

I pulled exhaust again, nope. I pulled the spark plug out it was little damp from fuel coming out of pilot hole, I let it dry a bit then tried again in next 30 minutes there was only one combustion on each cynlinder then no more firing.

I tried to start it with wide open throttle, after I dried the plug again, it fired 3 times then died. then it didn't fire again.

I cut the coil about an ¼ inch then tried again nothings different.

I got new coil new CDI new plug (not so new anymore so I ordered couple in) flawless carb and fuel and near perfect compression. yet she doesn't wanna go.

gap in spark plug is .45mm

what would cause it to not run?
why do I get spark out of the sled real good and it doesn't seems to in the cylinder?
I got fuel and compression so it must be spark not working in there.

Im completely bummed out here. any comment or tips to look for would be very much appreciated. thanks guys in advance

 

[Greg63]

Shouldn’t the plug gap be 0.18mm?

 

[kessun]

Shouldn’t the plug gap be 0.18mm?

I included shop manual for reference

 

[kessun]

I found out I was using BR9EG not BR9ES so I put new plugs in
checked stator 224v at 12 ohm, 17 when cranked
primary coil at .5 secondary at 12 ohm.
trigger coil, forgot what that put out but it was in good range.
checked carb boots, no crack.
kill switch unpluged, no start

but I got fuel spiking out from impulse line. from crank case to fuel pump. wasted fuel puddling down to exhuast manifold. I thought it was because fuel wasted from carb spark plug is quite damp.
nothing comes out of cylinder when I pull tho.
what are the chance that I just have flooded engine?

 

[racingX]

Pull your fuel pump apart….. it’s probably has rupture diaphragm. Filling your bottom end with fuel. If sled had engine failure like bearing the material usually finds it’s way in there and breaks the diaphragm. Rotary vale will not start flooded…. Even if you over prime your done. Might as well go for a coffee

 

[racingX]

O ya plug gab look at your spec.. bombi offers a metric and standard spec…. You just set you gap in metric with a standard feeler gauge… way way too big

 

[kessun]

O ya plug gab look at your spec.. bombi offers a metric and standard spec…. You just set you gap in metric with a standard feeler gauge… way way too big

Hey racingx, thank you for the comment.
my fuel pump has been rebuilt, nothing wrong with the pump. but it was flooding because air vent in my float bowl was blocked so it was creating vaccum in the bowl which cause the fuel to leak out the main jet, engine being tilted fuel was kept on entering into crankcase.
however, there are no more fuel going into crankcase, Im going to replace the fuel pump with new one and keep the old one as emergency parts.
for the spark plug gap, manual says 0.45mm which is .018 in inch. I checked the plug gap with imperial and metric and tried, not much of difference.
but after I fix carb flooding, engine was dry and it will firing up every pull, very poorly tho.
lots of backfire and with the HAC delete I wasn't too sure how I need to set the carbs at, Im gonna fiddle with it some tomorrow.
I got covid and had to stay home being sick but guess we will figure out if I fixed the damn thing or not!