Jdx8 fuel system

[Grnx854]

I have a jdx8 that I got a few months ago and finally getting time to work on but I have a small issue. I'm going threw the fuel system and there's a little in line electric fuel pump right after it fumes out of gas tank, I never new or know if this is supposed to b on the sled or did someone add it because they couldn't figure out the walbro carb? I'm sorry if I didn't see in any posts or internet searches. Thanks,Eric

[JDT]

There is not suppose to be an external pump on your sled.
Just the internal pump in the Walbro carb.

There is or should be a fuel pickup filter and check valve on the pickup tube in the tank. This is sometimes overlooked and can cause issues so don't forget to check and/or replace it. They only cost about $5.

[Grnx854]

I didn't think so, because I never seen it but new sled to me and my clymers manual doesn't show it either.. thanks

[JDT]

There probably was a reason someone went through the trouble to install a electric pump.

Vapor locking comes to mind. Plugged pickup or filter. Something that effected the fuel flow.

I would be very cautious of the crank seals also. Failed seal will cause the pump not to function.
The secondary pump will deliver fuel and than the bad seal will melt down the pistons.

Check the whole thing over closely before running it or it may well be a very short season.

[Grnx854]

How does one actually check crank seals, spray sum carb cleaner by them when running or ....

[JDT]

That usually works on the PTO side but I can't for the life of me figure out how one can do that on the MAG side.

If you don't know when they were last changed or if the sled has sat for years you would be wise to change them first.

They cost less than $10 for the pair and if they are bad and you run the machine it could cost hundreds.

[Grnx854]

Well got the old beast running, but.... I cleaned carb spotless, new carb kit\gaskets and\or diaphram. Ran pretty descent right away. Things I noticed are, lots of fuel and or bubbles or return line and a little doggy off the start, and if I choke it for more then 2 seconds it will pour fuel out carb. Ran for 2 days and went to family for xmas and come back and dam thing is flooding crazy unless I stay above 1/2 throttle or more. Things I noticed are wont idle or stay running unless 1/2 or more throttle and lots of bubbles in fuel line and return line, but runs great top end or anything above 1/2 throttle. I tried adjusting mixture screws all different ways and makes no difference other then when I shut or close the high end needle it has no top end. I havent looked at yet because its kinda hard to without taking whole dam cover off to see or do anything( biggest pet peeve of thsese sleds), but will be looking at again this wknd.

[jep_800]

Eric, Try looking at the thread I have posted here. You probably have to re-set your metering lever lower in order to stop that excess fuel from pouring out of the carb. I believe in the same thread there are data sheets that explain the adjustments for the Walbro carbs. It is very touchy, but once it is set correctly, it should idle and run fine. Then you just need to fine tune the idle mixture and high speed for optimum operation.

Jason

http://www.jdsleds.com/community/viewto ... 11&t=18783

[Grnx854]

I seen and did all proper adjustments, I just can't figure out why was some what fine when I got it going and 2 days after but then 5 days later it does this with no changes. But I haven't tore into it yet. Of all the ways to adjust the lever, I still am a little unclear the exact point to bend it but I'm not there yet. When I put together it was just a bit above base but that doesn't mean anything really since each will b a little different. But again was fine one day then the next was another story but will look at with cover off and see what I can see.

[Grnx854]

A little update for all. I seen sum gas under carb, I'm assuming that it came from the little weep holes things on side of carb that someone else had it coming out of once b4. I also noticed fuel in pulse line also which I'm thinking was from it flooding most of the time. I rechecked n cleaned carb and readjusted lever to just below base. Started and ran good and set idle ect. I noticed still lots of bubbles in fuel line and return. When I first got this going it never had any bubbles in fuel line just in return but now and still have in both. I drove and seems fine other then top end. If I hold wide open for more then 3 seconds or so it acts like someone hit the kill switch so I let off and pump it and after couple seconds settles out to stay running. So I try adjusting high needle to no prevail. I'm thinking I have lever a little to far down/lean cause kinda acts like it's starving for fuel but I still don't know what the air bubbles are from. I will next check out pickup line from or in tank because I'm sucking air from somewhere. Also, does any know how much fuel return is normal from this thing?

[400brian]

It is normal to have fuel and vapor going back to the tank in the return line. The supply line not so much. Are you running new lines, or old hard possibly cracked ones? Have you looked at the pickup fitting and line inside the tank?

[Grnx854]

All new lines and filter and tight, but my brother supposedly checked that. Now after I talked to him he just drained gas and said it was clean inside so that's what I have to check next. So moral of story is I should have done it it all myself like I usually do but...

[Grnx854]

I realize that fuel n vapor are meant to b in the return line but I have as much going out as I do coming in. I didn't think that pump be that powerful like but I don't know what normal is, haven't owned that long. Either way I gota check pick-up line in tank first.

[Grnx854]

Well fellows a little update for you all, I redid the pickup line in the tank since it was not laying down on bottom of tank so it was sucking air. So now i have the air bubbles and fuel figured out it tested again, then adjusted the lever arm to just below the base plate about .006 and drove and everything seems good now. My only problem now is it still seems doggy out of the hole, if i screw the idle mixture out more it doesnt improve it and just messes with the idle to much, idk. I guess i keep trying more in future unless anyone else has any better ideas.