JDX8 Problems

JDman21 · Post by **JDman21** » Sun Feb 05, 2006 4:56 pm

I took my 73 JDX8 out for a ride yesterday in the field, I hit 60mph. I took it on 4 long runs and around the yard. I parked it and went to put my shields and everything back on and adjust carb. When I am going fast and let off and hit it again sometimes it dies or takes a bit to pick back up. So I went to start it and it wouldnt start. So I took plugs out and the left one was hot and the ouside was kind of blue, the other plug was fine. There was steam coming from the left cylinder. Put plugs back, still nothing. This morning nothing, but about 120psi in both. Changed plugs ran for about 10 seconds died. Wont start. Plugs are kind of wet and black. Couple questions. Why wont it pick back up sometimes? What is the gap on the plugs? Any other ideas? I was so happy it was working great than nothing.

Thanks

JDman21 · Post by **JDman21** » Sun Feb 05, 2006 4:59 pm

Forgot to add I dont think I have spark on all 4 of my newer plugs. I threw in old ones thats when it ran for 10 seconds.

Danzig · Post by **Danzig** » Sun Feb 05, 2006 5:18 pm

You sound alot like me a year ago. After my endeavor this weekend, I would recommend changing your crank seal or seals as you see fit.

What type of plugs are you running?
Is the carb setup correctly?

As I have questioned in the past and went to school on the mechanics of a 2 cycle engine from a couple of guys on here. Compression can ge good but your fuel mix can be running out the bottom end of your motor, this will cause a lean condition and that means a hot engine and next you will have a melt down. Ouch $$.

Be sure your carb is setup correctly, you have good spark, clean points and you already have compression, be sure to check your pulse line and make sure it isnt sucking air rather than getting vacuum from the crankcase.

JDman21 · Post by **JDman21** » Mon Feb 06, 2006 8:08 pm

I took the carb apart and I swear I put it back together right, but now I have gas going through the pulse line.

JDman21 · Post by **JDman21** » Mon Feb 06, 2006 8:09 pm

I took the carb apart and I swear I put it back together right, but now I have gas going through the pulse line. Before that I had it to run and when I would rev it up it wouldnt pick up good and if I gunned it it would die.

JDXsand00s · Post by **JDXsand00s** » Mon Feb 06, 2006 9:28 pm

if you got gas in the pulse line your engine sounds like it is running rich. you should lean your carb down a little but be careful because you could lose a piston if you go to far. also pull off the gas feed and pulse line from the carb and pull it a couple of times, this sholud clean the engine out of gas. good luck.

JDman21 · Post by **JDman21** » Mon Feb 06, 2006 10:32 pm

I got it running, but oil was coming out of exhaust so I dumped some gas in and than it ran fine. So I took it out for a ride and adjusted the carb. It has great pick up and doesnt bogg down, but my high speed needle is as far down as I can go with the spring on top. Than I was adjusting it and it died. Now I have no fuel. had to push it 30ft. to the garage.
My question is that something isnt right if the high speed needle is all the way down, right?

Thanks

Danzig · Post by **Danzig** » Mon Feb 06, 2006 10:35 pm

My needle is set out about 2.75 turns. Careful with this because you are causing a major lean problem.

400brian · Post by **400brian** » Tue Feb 07, 2006 2:46 am

I'm not 100% clear on this. But from what I'm hearing, it sounds to me like you have a problem in the carb. Either a ruptured diaphram, or it is assembled incorrectly.

Two things make me say that:

1) You shouldn't have fuel going through the pulse line under any normal circumstances.

2) The fact that you have the main needle screwed all the way in, suggests that fuel is coming from somewhere else.

I suggest you resolve the fuel in the pulse line problem, them put your carb mixture settings back to the book settings and start over.

Did you rebuild the carb, or just take it apart ?

I suspect you need new parts.

JDman21 · Post by **JDman21** » Tue Feb 07, 2006 8:06 pm

I did rebuild it. Sometimes gas runs through the pulse line and sometimes it doesnt. I also read that the metering plate has gaskets under it and they have to line up perfectly with the hole, but mine doesnt and I tried moving the gasket and the only way I can get it to line up perfectly would be if I make the gasket hole bigger. Is that what I'm supposed to do?

400brian · Post by **400brian** » Wed Feb 08, 2006 2:52 am

I wish I could give you a definitive answer here.
As I can't see what you have going on, I really can't say if gasket mis-alignment is causing your problem or not.
I know for sure you can't have fuel in your pulse line, and have the engine run right.

Did the problem for sure start after you took the carb apart?
If it did, good chance it was something you did or did not do.

I suppose it could be possible that the diaphram you put in, could be bad right out of the box.

I'm not being too helpful here, maybe someone else has some good ideas?

JDFanPa · Post by **JDFanPa** » Wed Feb 08, 2006 1:18 pm

Sorry hadnt answered sooner

I really cant answer the metering gasket dilema other than have had misstamped gaskets in other carb kits before. If you can only line it up by enlarging the hole you may have to try it at this point. Would be great if you had a dig cam and could post pics of this.

2) If you can run the sled off idel with high speed turned all the way in you have most likely an inlet needle either stuck open,loose or not seating some way. This will make the sled run very rich also which would cause the oily exhaust and possibly the pulse line gas issue also the misaligned gasket could be letting gas in there all the time

3) I dont think you have fuel going through the pulse line out of the carb but rather a flooded motor and its spitting out the crankcase into the pulse line and if you have this much gas in the crank its going to hurt how the sled runs

You should pull the pulse line and pull the sled over and see how much gas spits out of the crank the other side cylinder may have a plug you can remove to do the same also if you can get it started start the sled up with pulse and supply line off and hold the throttle a lil over iel and let it burn asmuch gas out of the motor as possible it will also push more out the pulse line running.

So aslong as we are dealing with a good motor good compresion and spark. It really seems that this misaligned gasket issue is probably causing most of the problems. Without being able to see this hands on or atleast a pic the best thing to do would buy a new diaphram kit for the carb and start fresh and make sure the inlet needle is seating correctly