Jdx8 help!

[Jdx875]

Awesome, glad to know im on the right track lol, sleds are a love hate relationship. they are fun when when your riding but the rest is alot of trial and error. i can get the rebuild kit for the tillotson locally for 30$ so im going to give it a whirl, i have an old manual for my model and it says the metering arm is set flush, so maybe thats whats going on here is they tried to set it to the book on the sled and its set too high. if all else fails i will try and track down a wra-31.

im going to mix the gas 50:1 on the dot and adjust the carb accordingly and see where that gets me before anything else, then a carb rebuld once parts show up.

Thanks again for all the input ill let you know how she goes!

[Kurts]

I would focus your efforts on the carb. As long as the ignition coils, exciter coils, points, and condensor are in good shape, there is no real reason the points won't work on a well tuned engine.

For example I've been running a points setup on my 295/s for years with no real issue. Everyone here says it'll foul plugs and everything like that, well since I got it tuned well, I've not changed the plugs in like 3 seasons.

As for tuning, I have a few pointers.
1. Decided on a oil/fuel mix and stay with it. Contrary to most people's belief increasing the oil mixture actually leans the engine out. It isn't a large effect, but it's there. Personally I run Klotz synthetic at 40:1 in my 295.

2. The plugs should not be wet, if they are wet it is way way rich.

3. Do not take it for a long runs until you are sure it's right. The engine will survive short bursts extremely lean, but not long ones. If the plug gets much lighter than the color of a candy bar your probably getting close to being lean.

4. If it was me I'd just ditch whatever carb is on that thing, and put a mikuni round slide on it. Much easier to service and repair. The tilly/walbros are easy to tune (just turn a screw), but much harder to service and understand.

[Jdx875]

That's what I'm thinking soon. I got a video of it running today. It fouled the plug pretty fast and the idle was lower that what i set it to yesterday when it was warm

The video shows the spark I got, looks better in person.
And another video of just after startup still not at operating temp.

Got some air bubbles in the fuel line, and I also noticed in my primer line looked like it was sucking some fuel in. Not much but that can't help my situation so I'm going to remove the line and plug that spot off on the carb so it doesn't suck air off.

The idle goes way down and it starts running on one cylinder as seen in the video I can pull the plug off and get zapped a bit If I hold the boot slightly above the spark plug it randomly fires that cylinder.

Pictures show the plugs after that situation happened just idling.

https://youtu.be/zI4yGt6tpyo

[Jdx875]

So I think I have it figured out now after getting a tillotson service manual and seeing how it actually works.(I'm used to slide type carbs)

The screen that stops the throttle basically shouldn't be used to set your idle but to hold the throttle plate in the correct position so as it only runs on the idle circuit. If it's adjusted too much it will draw more fuel as if you were trying to go somewhere.

So with this being found out I've set it again and so far no fouled plugs but it is late and the neighbours probably hate me so I will find out tomorrow.

I've attached pictures for some info in case anyone needs it..

[Jdx875]

Is this considered a bad diaphragm? It pumps fuel, the fulcrum arm was set a little high when I took it apart, lowered it back to level as per manual (tillotson carb) now my fuel line has air in the first section seems like it's using more fuel than it's drawing. Filter is full those below is full but those from tank to filter looks empty

[jep_800]

Have you got the rebuild kit? I would just replace all the diaphragms and gaskets so there is no question about them. You should be correct with a flush metering arm.

Have you checked your impulse line yet? I think you mentioned seeing a little fuel moving in it, but not much. So after you've rebuilt the carb, you should be able to put on a correct reinforced rubber line for your impulse. These are stronger and won't collapse. Just make sure they are clamped well so that you take advantage of all the crank case pressure, which of course pumps your fuel. Then I would think you would have everything covered.

Jason

[Jdx875]

That was the primer hose that I could see fuel but determined the was just pulling the remaining gas in the line not from the tank...

I just put on a clear hose on the pulse line and I've definitely got fuel in it. So what part of the carb should I be looking at? I'm still waiting on a rebuild kit but if I could take a look at what part is the cause and maybe try and fix it temporarily just to be sure that's it it would be nice..

Here's a link and a picture.. https://youtu.be/nZTvkx2blOs