79 john deere spitfire

john-deere-340 · Post by **john-deere-340** » Tue Jan 08, 2008 9:54 pm

I finally got my spitfire running but after its warms up it seems to be really boggy. Ive cleaned the tank, filter and carb and replaced all the hoses and a new fuel pump. The motor had a complete overhaul with pistons, rings, crankshaft bearings and seals. the motor is brand new with only about 4 miles put on it after it was running. This has me boggled Does anyone know what it could be? My repair manual that I have for it doesnt say anything. But when it runs it will lift the skis off the snow not much but enough on a little sled like that to give u a scare. Please help.

Eagle103 · Post by **Eagle103** » Tue Jan 08, 2008 11:07 pm

I'm not sure if you've had the sled for a while but I've owned my 79 since the early 80s and it has always acted that way where the power goes down as it heats up. I've always just assumed it was normal for that sled. At temperatures below about 10 degrees it isn't much of a problem but if it gets warmer I'll stop and throw some snow on the engine once in a while.

smitfire · Post by **smitfire** » Tue Jan 08, 2008 11:15 pm

sounds like something in carb, try turning out the air screw a little and clean or install new pilot jet,

JDT · Post by **JDT** » Wed Jan 09, 2008 2:11 am

Free Air engines run best when it is 35 below. The warmer it gets the hotter they run and will stop running all together at some point. If you are hitting WOT that point comes on real soon at 25 above.
Todd

john-deere-340 · Post by **john-deere-340** » Wed Jan 09, 2008 2:26 am

Ya the carb is rebuilt complete wtih pilot jet. I just got back from a 30 mile run on it and it did the same thing. and its around -15 degrees celcious. I was running in powder with it so the engine always had snow hitting the motor but that didnt do anything. so im completely confused. I bought this sled about 4 months ago with only 484 miles/ km/s on it. its mint shape with a few cracks in the hood but nothing major. Nice sled until it gets too hot...lol

b00stinGTP · Post by **b00stinGTP** » Wed Jan 09, 2008 2:41 am

Does it bog down at a particular speed? Or does it bog all over the place once warmed up

john-deere-340 · Post by **john-deere-340** » Wed Jan 09, 2008 3:37 am

it bogs out all the time when its warm. I'm confuzzled on what it would be.

Danzig · Post by **Danzig** » Wed Jan 09, 2008 4:06 am

Cheap gas? Bad clutch springs? the list can go on.

john-deere-340 · Post by **john-deere-340** » Wed Jan 09, 2008 9:19 am

Has nothing to do with gas or clutching Brand new clutch on it but i got it licked now i think and hope i will let you all know.

Spitfire79 · Post by **Spitfire79** » Thu Jan 10, 2008 5:24 pm

Dos the track turn fre? I'm wondering if the bearings on the front cross shaft are seized or worn. This causes the shaft to bind. It may turn free when lifted in the air but once weight is placed on it then it may bind.

This sled is direct drive and everything needs to be in order

Jeff