1996 GTS 587 turns but won't fire

[mokofoko]

I could really use some experienced thoughts as I'm short on time. I usually have no trouble starting my '96 GTS after winterizing and a long break. This time (only here 2 weeks), it momentarily fired up, died down within a few seconds and will no longer start. The engine turns over fine and has good compression, but never fires.

Things I did:
1. (before winterizing): I did rebuild the mikuni carb with a cheap $10 china/ebay washer kit (I know, bad idea). I did not replace the needle/seat. I plan to order and replace with a genuine mikuni kit later, but the carb seemed to be working okay with the cheap kit last season, ran about 10 hours.
2. I just replaced all fuel lines with some recommended gates hose, cleaned fuel filter. Replaced the fuel selector as well. 100% certain I hooked it up proper, and primed the fuel to the carb with a suction hose.
3. I bought new br7es spark plugs (always used these instead of br8es) and gaped it to the recommended 0.020" (but it always previously fired at the stock 0.034")
4. I've tried pouring a little gas directly into the spark plug holes, always got me started from cold before. I also tried pouring fuel with oil premix directly into carb, same result, just turns.
5. I previously used 87 regular ethanol gas before, but switched to non-ethanol fuel last year. The original fuel line connecting to the crankcase was fully gunked-up, and I tried to scoop out any sludge that might have been blocking the crankcase nozzle.

Unknowns:
1. The battery is really bad and I have to charge it up after ~30 seconds worth of cranking. I tried turning over with a jumper pack attached, it also just turns (fast) in this scenario.
2. Could problem be a bad ignition coil?
3. Even if the carb kit is bad, shouldn't the engine still at least fire briefly with some gas poured in per above?

Is there anything else I can test in the short-term before I give up and get a new battery and carb kit next time? I'm only here another week and I replace these stupid powersport batteries every 6-12 months (gone the next 6 months), but if this is the likely culprit, I'll just run out and grab one.

Thank you!

 

[artr]

Test for spark either with an inline tester or pull a plug and ground the threads to engine ground while cranking. There is also probably a resistance test for the ignition coil and plug wires in the shop manual if you do not get spark.

 

[mokofoko]

Test for spark either with an inline tester or pull a plug and ground the threads to engine ground while cranking. There is also probably a resistance test for the ignition coil and plug wires in the shop manual if you do not get spark.

Just jumped the battery with the car, so it's not the battery itself. I also just attached a wire up into the spark plug connector (touching the inner metal sleeve) and brought it to the plug when turning the engine over--no spark was detected. I'll see if I can figure out how to do your method next.

 

[mokofoko]

I'm going to take the fuse box up into the front compartment and take a look inside. I'm hoping it's just a blown fuse (does the ignition coil have one?), otherwise it couldn't hurt to order a new ignition coil. I guess I'll be spending some time reading through the manual tonight!

 

[2strokeboy]

So you need a good battery first off. Check compression?

 

[artr]

I missed the part about your bad battery. That can effect the spark as well as cranking. First, never jump your ski battery from a running car or a jump pack that is charging - you could blow the MPEM. It is ok to jump a free standing car battery or a non-charging jump pack if it is equivalent to normal battery voltage. It would not hurt to check the fuses. To test spark, pull a plug and then snap the plug into the wire boot. Hold the plug by the boot and bring the plug threads or the bottom electrode in contact with a clean engine ground while cranking and look for a blue spark across the plug electrode gap. If you have spark you can also check compression for problems

 

[Stevie96xp]

Yeah no spark could be coil or a bad fuse. I hope you didnt blow something with the jump.

 

[mokofoko]

I missed the part about your bad battery. That can effect the spark as well as cranking. First, never jump your ski battery from a running car or a jump pack that is charging - you could blow the MPEM. It is ok to jump a free standing car battery or a non-charging jump pack if it is equivalent to normal battery voltage. It would not hurt to check the fuses. To test spark, pull a plug and then snap the plug into the wire boot. Hold the plug by the boot and bring the plug threads or the bottom electrode in contact with a clean engine ground while cranking and look for a blue spark across the plug electrode gap. If you have spark you can also check compression for problems

Thanks so much. I'd already jumped it with the car running, whoops. I'll make sure not to do that again.

I did as outlined, pulled each plug separately and grounded to the engine plate. I DO see sparking within each gap. So I guess the ignition coil is fine and I can leave the fuse box alone?

So if the plugs are sparking and I've poured about a teaspoon of fresh gas in each plug hole before trying to turn it over, is there any reason it shouldn't fire briefly, even if the carb needs another rebuild? I did have it compression tested maybe 2 years ago and it came out fine, with no work done outside of the carb rebuild.

 

[mokofoko]

Yeah no spark could be coil or a bad fuse. I hope you didnt blow something with the ju

I guess I'll just have to get a new battery, even if it's sitting unused for the next 12 months. If the plugs are sparking though, all should be good, correct?

 

[2strokeboy]

Thanks so much. I'd already jumped it with the car running, whoops. I'll make sure not to do that again.

I did as outlined, pulled each plug separately and grounded to the engine plate. I DO see sparking within each gap. So I guess the ignition coil is fine and I can leave the fuse box alone?

So if the plugs are sparking and I've poured about a teaspoon of fresh gas in each plug hole before trying to turn it over, is there any reason it shouldn't fire briefly, even if the carb needs another rebuild? I did have it compression tested maybe 2 years ago and it came out fine, with no work done outside of the carb rebuild.

Check compression it should run. If you dont have one already I think you can rent them places or you could buy one.

 

[artr]

if you see spark and put gas straight in then check compression as mentioned.

 

[Stevie96xp]

I guess I'll just have to get a new battery, even if it's sitting unused for the next 12 months. If the plugs are sparking though, all should be good, correct?

Yeah should be if you got compression and spark suck will run atleast with fuel down the carb

 

[mokofoko]

if you see spark and put gas straight in then check compression as mentioned.

Thanks all. I ran over to autozone to borrow a compression tester. Using a battery pack jumper at the moment as the powersport battery is now toast. Both cylinders are reading identical at 137-138 psi with the throttle wide-open, which is supposedly okay for a 587.

I can get a battery on order, but is there anything else I can check? I've never once had a problem firing the engine after dropping a teaspoon of gas into each cylinder, really confused here.

 

[burtshaver2021]

After reading your original post I would start by getting the new battery of course and changing the new plugs you put in and gapped. Put in a new set without gapping them. Then try starting it with a little bit of premix in the plug holes.

 

[Stevie96xp]

Thanks all. I ran over to autozone to borrow a compression tester. Using a battery pack jumper at the moment as the powersport battery is now toast. Both cylinders are reading identical at 137-138 psi with the throttle wide-open, which is supposedly okay for a 587.

I can get a battery on order, but is there anything else I can check? I've never once had a problem firing the engine after dropping a teaspoon of gas into each cylinder, really confused here.

Him well compression is good so that’s a plus if you got spark then it should fire with some. Fuel down the throat but my only guess is that the jump pack is making something not happy when you crank but you could also check your rotor valve make sure it’s spinning. You could have flooded the crank case fresh plugs sometime they won’t fire when there in the hole but fire when there out. seen it a bunch before

 

[mokofoko]

Thanks all. I got a brand new battery charged up. Still won't turn over, but at least no battery issues... I tried swapping in the old plugs as well, and they do also spark but no firing...

 

[mokofoko]

Him well compression is good so that’s a plus if you got spark then it should fire with some. Fuel down the throat but my only guess is that the jump pack is making something not happy when you crank but you could also check your rotor valve make sure it’s spinning. You could have flooded the crank case fresh plugs sometime they won’t fire when there in the hole but fire when there out. seen it a bunch before

I noticed that the plugs were saturated in gas when pulling. With the plugs out, there's plenty of gas mist being shot out of both cylinders. Could the crankcase be flooded with gas? And if so, is there anything I can do besides leaving the plugs out and giving it time to evaporate? I think i read elsewhere that someone flooded their engine and they actually took the engine out and shook it out... not an option for me.

 

[Stevie96xp]

I noticed that the plugs were saturated in gas when pulling. With the plugs out, there's plenty of gas mist being shot out of both cylinders. Could the crankcase be flooded with gas? And if so, is there anything I can do besides leaving the plugs out and giving it time to evaporate? I think i read elsewhere that someone flooded their engine and they actually took the engine out and shook it out... not an option for me.

Yeah there is probably a bunch of fuel is the crank you need to spin it over with the plugs out fuel selector in the off position and the throttle wide open and then crank till the most goes away make sure to give the starter brakes tho

 

[mokofoko]

Yeah there is probably a bunch of fuel is the crank you need to spin it over with the plugs out fuel selector in the off position and the throttle wide open and then crank till the most goes away make sure to give the starter brakes tho

I've been giving that a try today. I just tried with the plugs back in now, and it's consistently starting off by giving about a second where it sounds like it's trying to fire. Of course, gas still all over the plugs. I guess I should just pull the gas line to the carb for now, with the assumption that it's leaking into the case?

Still seems like progress compared to before!

 

[Stevie96xp]

I've been giving that a try today. I just tried with the plugs back in now, and it's consistently starting off by giving about a second where it sounds like it's trying to fire. Of course, gas still all over the plugs. I guess I should just pull the gas line to the carb for now, with the assumption that it's leaking into the case?

Still seems like progress compared to before!

Yeah man it sounds like it’s just extremely flooded

 

[Stevie96xp]

I've been giving that a try today. I just tried with the plugs back in now, and it's consistently starting off by giving about a second where it sounds like it's trying to fire. Of course, gas still all over the plugs. I guess I should just pull the gas line to the carb for now, with the assumption that it's leaking into the case?

Still seems like progress compared to before!

Definitely pull the fuel line going to the carb

 

[mokofoko]

Yeah man it sounds like it’s just extremely flooded

That does seem to be the case. After pulling the fuel lines to the carb, I can eventually get it to fire up and run for something like 10+ seconds, and that's with no fuel being fed in (did not realize it could run for that long without pulling gas into the carb)... As soon as I hook up the fuel lines again and briefly start, it'll refuse to fire again, flooded. Rinse and repeat, did this about 3 times just to be sure. Has to be the carb leaking, and I'm going to order a new mikuni kit so I can get to work on this the next time I'm here.

Not the best outcome, but happy to have at least narrowed the issue down. Thanks for your input, everyone!

 

[burtshaver2021]

That does seem to be the case. After pulling the fuel lines to the carb, I can eventually get it to fire up and run for something like 10+ seconds, and that's with no fuel being fed in (did not realize it could run for that long without pulling gas into the carb)... As soon as I hook up the fuel lines again and briefly start, it'll refuse to fire again, flooded. Rinse and repeat, did this about 3 times just to be sure. Has to be the carb leaking, and I'm going to order a new mikuni kit so I can get to work on this the next time I'm here.

Not the best outcome, but happy to have at least narrowed the issue down. Thanks for your input, everyone!

You can order the carb kit from OSD parts.com it will come with new needle and seat

 

[Stevie96xp]

That does seem to be the case. After pulling the fuel lines to the carb, I can eventually get it to fire up and run for something like 10+ seconds, and that's with no fuel being fed in (did not realize it could run for that long without pulling gas into the carb)... As soon as I hook up the fuel lines again and briefly start, it'll refuse to fire again, flooded. Rinse and repeat, did this about 3 times just to be sure. Has to be the carb leaking, and I'm going to order a new mikuni kit so I can get to work on this the next time I'm here.

Not the best outcome, but happy to have at least narrowed the issue down. Thanks for your input, everyone!

Yeah man sounds like your carb needs a rebuild and the. You should be good