99' SUMMIT 670X not running??? HELP

wags19 · Oct 14, 2011

hey guys im new to this forum and im need of assistance. I rebuilt the top end on my sled this last spring, and im trying to finnish it off for the up coming season. Its all back together, but i cannot get it to run. I think its a fuel issue, because it seems to have good spark (new coil, wires and plugs). I pull and pull and pull on this thing and get nothing more then a very small and short fire???
When I took the sled appart, I did not mark where all my fuel lines where. I figured I could get that info from my shop manual, I was wrong. I have the DPM system on this sled and my manual doesn't show anything with the DPM in the drawings.
I also found that I had fuel in the actual DPM after a bit, not normal either (I think). Does anyone have a schematic and or drawing that I could use to get the proper routing for my fuel lines? Or does anyone know where else I should be lookingfor my problems?

Thanks Guys

670Xpower · Oct 20, 2011

Send me your email address or cell number. I have two 99 summit X's I will take detailed pics and send them to you

BBP · Nov 12, 2011

I just had 99 670X in the shop with identical symtoms, it was a bad rotory valve plate. Pull the carbs & look through the intake as you roll the clutch over. You can see the plate as it rotates.

wags19 · Jan 2, 2013

BBP said:
I just had 99 670X in the shop with identical symtoms, it was a bad rotory valve plate. Pull the carbs & look through the intake as you roll the clutch over. You can see the plate as it rotates.

I know this is an old post but I am having the exact same issues, only I was looking into rebuilding the air pump and fuel pump. I'm not even sure if you can even rebuild either of these.

So I will be looking at the rotory valves as soon as I get home in the morning. What should I be looking for? What sort of damage will I see if this is my problem?????

HELP!!!! I've been chasing this problem for the last 2 years, since I melted one of my pistons. The damage on the piston was on one cylinder only, and it was on the exhaust port side. Also the the cylinder walls are all good, no damage. I just lightly honed the cylinders and replaced both pistons and rings.

Let me know what to look for. Thanks

summit800 · Jan 3, 2013

If you had it apart, there is a setting for the rotory intake plate,it has to be at a certain demention at tdc they even make a plastic degree wheel to set them , if you didnt mark it at tdc before you removed it then it is probley out of time for the air fuel mixture

wags19 · Jan 3, 2013

I don't think my problem is with the rotary valve. I took the carbs off and turned the engine over, there doesn't seem to be any damage at all when I look in???? Back to square one I guess???? Should I be looking at my air pump? There seems to be tons of fuel almost like its flooding. Ideas?????

Red-eye · Jan 3, 2013

Was the fuel valve left on and flood the crankcase? Old fuel in the tank and won't ignite?
Pull the plugs and see if fuel is spraying out. Wasn't there a crank drain on that engine??
Spray fresh fuel in the carbs and see if it fires.

wags19 · Jan 3, 2013

The fuel was shut off when I first go to start it after opening the fuel valve, I prime it 2X, make sure the kill switch is pulled up and pull it over. It will try to fire on the first pull and almost run but only for a second. Then it's like it's flooded and won't fire at all. And there is a very strong fuel smell. It's flooded I as far as I can tell. The compression is so good on this thing that I hate having to pull and pull and pull. It used to start on the first or second pull every time. I'm at a loss

Red-eye · Jan 3, 2013

Shut the fuel off and pull the plugs and pull the engine over to clean out the gas. Shut the fuel off and pull the air box. Fill a spray bottle with FRESH mixed gas and run the engine with the spray bottle spraying into the carbs. Might need a buddy to help. if you cand keep it running with the spray, then you know the engine and spark are good.

Red-eye · Jan 3, 2013

I have seen old gas kill the plugs too. Is there fuel in the impulse line of the fuel pump?

wags19 · Jan 3, 2013

It's all new fuel. I completely drained the fuel tank when I replaced pistons and rings. The only chance of old fuel may have been in the engine it's self or maybe low points in the fuel lines. I have also cleaned the carbs.

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99' SUMMIT 670X not running??? HELP

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