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Discussion Starter · #1 ·
I have a 99 mxz 670 ho. It ran fine until last weekend. Now, whenever you hammer on the gas, it takes off hard, then falls completely on it's face and bogs down. backing off the throttle completely for a bit then getting back on it works for a second again, if you just hold it at half-open it kinda wants to pull but won't rev up. Occationally it'll stall completely and won't start again. I did have the engine out last weekend to fix the steering bushing strap, with no problems before that, and so therefor assumed it had something to do with the work i did...but i quadrouple checked all of that, with no problems found (engine allignment, fuel line kinks, etc).

I've taken the carbs apart, found nothing wrong, removed the fuel filter for testing, put isopropyl in it, changed belts (not to a new one, but a usable spare), plugs, the norm....then i pulled the pump, and if i blow into the pulse port from the crankcase, i can get air to leak out of the intake or output, don't remember. i'm pretty sure it's the pump at this point, i believe it would explain all of my problems, but there's no rebuild kit for them and they're $100, special order so no return. I'd like to be sure that this is the problem.

Any ideas? thanks...
nik
 

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Crimped/kinked fuel line - Similar thing happened to me after cleaning my carbs - I couldn't get mine started though. Seemed like the line wasn't really kinked, but it was. Try that...
 

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I have the exact same sled and had the exact same problem, in my case it was the fuel pump but don't waste your money on a new dealer pump, go to royaldistributing.com and get the high-output 61L/h pump for half the price and I assure you that you'll never run out of fuel on the top end again, I'll see if I can find you the part number and post it for you.
 

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Discussion Starter · #7 ·
ok, thanks whitetrash, i'll be checking that out. 700 GSE....one of the things i checked very closely while trying to find problems that may be related to me having moved the engine was fuel lines, all are clearly visable and looked ok, so i don't think that's it.

thanks a lot, guys!
nik
 

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Discussion Starter · #8 ·
whitetrash, do you happen to recall if the fuel intake on the pump from royal is the same size as the fuel line on the sled? my sled is a ways from where i am, so i need to have all the parts with me when i go to put it back together...

thanks
nik
 

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Fro - like I aid - I did the same thing - looking straight at the fuel lines - didn't look kinked or nothin' - but my sled wouldn't start! So I removed the airbox, took the carbs out, removed the fuel line, re-ran a slightly differefent way, over rather than under, and voila! Keep in mind, after cleaning my carbs, they were dry, hence no start, but had they had fuel in the bowls, it woulda started, and most likely fell on it's face like yours... Can't hurt to try... Mind you, I agree it could be the pump.
 

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The replacement pump actually has a slightly smaller inlet size than the original fuel line. The original clamp would not put enough squeeze on it but a small gear clamp gets the job done so make sure to have one ready. You will also find that the mounting holes and ports don't line up properly but you can remove the pump body screws and re-clock the body to get things to line up pretty close to stock.
 
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