1978 spitfire, clueless please help guys!

[Paintdan85]

Hello Guys,

In need of some serious help!!! I started a new thread because I stopped getting responses back on the last one, hopefully this helps! I got a 1978 Spitfire off my buddy that had been sitting for years, after replacing the carb, it will idle, but nothing past idle. The carb that I bought, according to some of the prior help mentioned that the jets where way off and it had a 2 slide valve Vs. stock 2.5. I also told to replace the seals, seals and seals.

So I tore down the whole engine, replaced all gaskets and seals from the ground up, I also added all new Stainless steel hardware because everything was rusted, I also replaced the stator with a NOS stator, I replaced the Coil pack and CDI box, I also bought a new Carb with the 2.5 slide valve and jetted to factory specs .30 pilot and a 210 main jet. Since it was sitting outside for a wile, mice got into it and chewed a bunch of wires, so I replaced all the wiring since I had the motor out.

I got everything back together and ... same thing, idle is a lot better then before rebuild, but nothing past idle, you can pull the throttle in and you can hear it sucking in more air but no higher RPM's with the throttle opening.

So... yes the throttle is opening all the way up and closing when letting go of the throttle, I have spark on and good compression on both cylinders, I re-timed the engine, the muffler is free flowing (no obstructions) I removed the comet torque converter just to make sure that wasn't causing the hold up, I changed the main jet bigger and smaller then the factory setting, I rebuilt the whole engine, added a new fuel pump (tried 2 different carbs and 2 CDI boxes, I just dont know what else to look for . . . I have a ton of money invested in this project and It needs finished up!!!

I just dont know what else could be the cause of the engine not revving up as I pull that throttle, I have to be passing something up and I just don't know what ??? Any of you guys have / had the same issue or not???

Please help guys and tell me what Im doing wrong!!! Ready to pull my hair out over here!!!
Thank you guys for your help

Dan

[75522]

I didn't see you mention the fuel pump. The Spitfire has a vacuum actuated fuel pump. They are relatively cheap, and considering all the other replaced parts, I'd replace that too. If not, at least take it apart, clean it out, and reinstall. Also, check the hosing for splits/cracks, even a small split can cause enough air to leak so that the fuel pump is not drawing the proper vacuum. It may be providing enough fuel at idle, but not enough once you rev up. You shared that you hear the carb pulling in air, and that the spark was good, the only thing left in the equation is fuel...

Hope this helps.

[sledhead16]

would it rev up with the belt off? make sure the impulse line is black thick wall rubber, as mentioned get a new fuel pump. Sounds like a fuel delivery issue, or a driveline component hanging up. also the big jd snowmobile facebook group is usually visited more often a day for help.

[SS440-80]

My first idea... the CDI-unit, but since you have tried others working CDI:s it can't be that.
With a seriously rebuilt engine with new seals and gaskets, the possibility of lean mixture by drawing in air the wrong way less than zero.
And with a new carb it should work.
Can you get the motor to rev up if you take of the air box and also take of the exhaust system? Just to be sure that it's not the inlet or outlet....
And you can also feed the carb with a bottle of fuel hold above the carb, with a hose to load the carb. That way you can exclude gas tank, fuel line and fuel pump.

If everything is right and it just refuse to rev I think that you have to look for wrong parts on the sled. Maybe you have a a wrong ignition coil, someone could have mounted a coil for a later Kawasaki when you should have a Kohler type? Many years ago I bought a Yamaha Viking 540 that wouldn't rev. It started and had a good idle, but as soon as I hit the trottle it would die. Turned out that someone had mounted a coil from a early SRV (same engine, different magneto) and the ignition timing went nuts.

[Paintdan85]

I didn't see you mention the fuel pump. The Spitfire has a vacuum actuated fuel pump. They are relatively cheap, and considering all the other replaced parts, I'd replace that too. If not, at least take it apart, clean it out, and reinstall. Also, check the hosing for splits/cracks, even a small split can cause enough air to leak so that the fuel pump is not drawing the proper vacuum. It may be providing enough fuel at idle, but not enough once you rev up. You shared that you hear the carb pulling in air, and that the spark was good, the only thing left in the equation is fuel...
Hope this helps.

Hello, Yes I did replace the fuel pump with a new one also! Sorry forgot to list that!

would it rev up with the belt off? make sure the impulse line is black thick wall rubber, as mentioned get a new fuel pump. Sounds like a fuel delivery issue, or a driveline component hanging up. also the big jd snowmobile facebook group is usually visited more often a day for help.

thanks for the heads up, I was unaware of the Facebook group! As for the impulse line, I used thick wall carb line, I would hope that it wouldn't colaspe on itself! Also I did remove the clutch altogether (just in case I put it back together and it wasn't opening up and causing the motor not rev up)

My first idea... the CDI-unit, but since you have tried others working CDI:s it can't be that.
With a seriously rebuilt engine with new seals and gaskets, the possibility of lean mixture by drawing in air the wrong way less than zero.
And with a new carb it should work.
Can you get the motor to rev up if you take of the air box and also take of the exhaust system? Just to be sure that it's not the inlet or outlet....
And you can also feed the carb with a bottle of fuel hold above the carb, with a hose to load the carb. That way you can exclude gas tank, fuel line and fuel pump.

If everything is right and it just refuse to rev I think that you have to look for wrong parts on the sled. Maybe you have a a wrong ignition coil, someone could have mounted a coil for a later Kawasaki when you should have a Kohler type? Many years ago I bought a Yamaha Viking 540 that wouldn't rev. It started and had a good idle, but as soon as I hit the trottle it would die. Turned out that someone had mounted a coil from a early SRV (same engine, different magneto) and the ignition timing went nuts.

Yep I bought a new CDI for the sled (this one didn't have one on it so I think I bought the right one (All the wires match up!)) but I bought another one (same type) and it doesn't make any difference (as long as I bought the right one to start with). The motor wont even try to rev up. . . I tried without the airbox and it would barely idle, let alone rev up, I haven't tried removing the exhaust yet, but I did put air thought the muffler and it didn't seem to build pressure at all, shaking it, it sounds empty. . .

The stator that I bought to replace mine, looks exactly like the one I took out, and according to the original owner, nothing was ever swapped out of this sled. . .


I was talking to my dad, he was thinking that It might have something to do with the ignition / timing, like the timing isn't advancing as I pull the throttle so the spark is behind??? Not even sure where to start with that...

Any other thoughts???
Dan

[Paintdan85]

Looking at the CDI unit, and still wondering if I have the wrong one, what do you guys have on your spitfires? Im looking all over the web and cant find any pictures, nor can I find one with a specific number to look up.

Thanks guys
dan

[Paintdan85]

Here is a video of the issue guys

https://youtu.be/4d6xIpuOpfo

[JDT]

Sounds like it is only hitting on one side in the video.....

[Paintdan85]

Sounds like it is only hitting on one side in the video.....

You mention it sounds like its only hitting on one side, if I got spark on both plugs when testing them without the engine running, would it be possible for it to be hitting on one side when trying to get it to rev? I just triple checked to make sure it was firing both plugs two days ago and they both fire when pulling the pull rope.


Dan

[JDT]

Many years ago I worked on a Spitfire that did the exact same thing as yours. Idle but wouldn't rev.

Replaced CDI and the same problem. After several days of frustration I borrowed a box from a working Spit and put it one. Problem gone!


I recall a post a year or two ago on this forum where the same issue arose. Again it was the CDI.

…………………………..

So you already replaced your CDI but you can have a bad CDI right out of the package.


In your video the engine sounds limpy or weak to me. That is why I suggested firing only on one side.

Easy to check. Let it idle for one minute and then feel the exhaust manifold or head and see if both sides are warm. Better yet shoot it with a infared thermometer.


…………………….


Your question about spark and then not firing. The dreaded "lack of fire undercompression issue". It is real and makes little since but it happens.

Could be a bad plug.


But I am still thinking you have a CDI issue.

[Paintdan85]

Many years ago I worked on a Spitfire that did the exact same thing as yours. Idle but wouldn't rev.

Replaced CDI and the same problem. After several days of frustration I borrowed a box from a working Spit and put it one. Problem gone!


I recall a post a year or two ago on this forum where the same issue arose. Again it was the CDI.

…………………………..

So you already replaced your CDI but you can have a bad CDI right out of the package.


In your video the engine sounds limpy or weak to me. That is why I suggested firing only on one side.

Easy to check. Let it idle for one minute and then feel the exhaust manifold or head and see if both sides are warm. Better yet shoot it with a infared thermometer.


…………………….


Your question about spark and then not firing. The dreaded "lack of fire undercompression issue". It is real and makes little since but it happens.

Could be a bad plug.


But I am still thinking you have a CDI issue.

Thank you for more info, so i still have a CDI that i still haven't sent back yet. I happen to plug it in (with the new jetting in the carb) and it sounds like the RPM's started to rise a little (enough for the torque converter just started opening a little) and then the same thing the sound of the throttle opening with no higher speeds. but at least its starting to gain a little speed, but still not enough to get the torque converter open. When I rebuilt the motor the stator was reading off with the omh meter, so I soldered new wires to the coils and the ohms read right afterwards (couldn't find a new or used startor coil pack on ebay for it) and looking on ebay last night to my surprise a NOS stator was listed! So I bought that this morning just to try a new stator also! So I will let you guys know when that comes in and I tear everything back apart again if that works . . .but i was thinking if I got the wrong CDI for it.

I still don't know if I'm using the right CDI since this one didn't have one in it to begin with, im guessing i have the right one, but I dont know . . .

Here is the one I bought, even though on Kimpex's website a John Deere spitfire is not even listed:

https://www.ebay.com/itm/Kimpex-01-143- ... :rk:1:pf:0

[SS440-80]

I think you should hunt for a original CDI-unit to test the engine.

When I check around for the Kimpex-number on your Ebay purchase, it only fits A-C, Moto-ski and Ski-Doo.
And when looking at CDI:s for Kohler-engines I find that the same number on a after market CDI has different price, so something must be different...??

J-D Spitfire: ADKX0114322 $52.70
http://www.psep.biz/store/john_deere_sn ... _boxes.htm



A-C El Tigre 5000: ADKX0114322 $60.28
http://www.psep.biz/store/arctic_cat_sn ... di_box.htm

[Paintdan85]

I think you should hunt for a original CDI-unit to test the engine.

When I check around for the Kimpex-number on your Ebay purchase, it only fits A-C, Moto-ski and Ski-Doo.
And when looking at CDI:s for Kohler-engines I find that the same number on a after market CDI has different price, so something must be different...??

J-D Spitfire: ADKX0114322 $52.70
http://www.psep.biz/store/john_deere_sn ... _boxes.htm



A-C El Tigre 5000: ADKX0114322 $60.28
http://www.psep.biz/store/arctic_cat_sn ... di_box.htm

Thank you for the info!!! I've been looking for a site like this to get parts off of other then just "ebay" What the hell, whats to buying a 3rd CDI ! lol . . . I'm starting to wonder if it might be the CDI, reason being I bought a 2nd CDI and tried it out when I was having idling issues and it made no difference. Well I was getting ready to pack it back in the box today to send it back, and i'm like what the hell, let me try it one more time since I now have the carb jetted right and things re-wired, and to my surprise it idles fine and starts to rev the engine just a bit to the point that the clutch just starts to open (not enough for it to grab the belt though) but better then the first CDI that i had no change in throttle at all.

I just bought the CDI listed from this site you had listed and i'm crossing my fingers that it is it! I will keep you guys updated!

[nick80lf]

https://www.newbreedparts.com/newbreed/ is another good source for Deere snowmobile parts. The owner of JDsleds.com owns New breed parts.

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[Paintdan85]

I think you should hunt for a original CDI-unit to test the engine.

When I check around for the Kimpex-number on your Ebay purchase, it only fits A-C, Moto-ski and Ski-Doo.
And when looking at CDI:s for Kohler-engines I find that the same number on a after market CDI has different price, so something must be different...??

J-D Spitfire: ADKX0114322 $52.70
http://www.psep.biz/store/john_deere_sn ... _boxes.htm



A-C El Tigre 5000: ADKX0114322 $60.28
http://www.psep.biz/store/arctic_cat_sn ... di_box.htm

So I got a response back from Kimpex, this is what they wrote when I asked if they carried a CDI unit for a Spitfire

"Hello Daniel,
Unfortunately I do not make or carry a cdi unit for your particular application, I see as you said that the 01-143-22 has been recommended by certain people for all kohler's however here at Kimpex we have not tested that theory , I might suggest you consult a John Deere or Kohler dealer or mechanic for confirmation. Sorry could not be of more help.
Thank you and have a great day."

So I don't think that rep knew what I was talking about Or Knew what she was talking about, but I don't think John Deere is going to give me an answer on that since they stopped making sleds in the early 80's and Kohler . . . they probably wouldn't have an answer for me either!

https://www.newbreedparts.com/newbreed/ is another good source for Deere snowmobile parts. The owner of JDsleds.com owns New breed parts.

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Hello Nick, yes I knew about Newbreedparts, I didn't know he was the creator of this forum!