79 Spitfire not making power
79 Spitfire not making power
Posted this in General but should have posted this here. Looking for a little help. Santa brought the girls a 79 Spitfire for Christmas, boy are they excited! Unfortunately, we are in Central WI (those in the area will understand that we are socked in with 40 degree temps and horrible fog, humidity has to be close to 100%) and while the Spit ran well on Christmas day and Firday morning. When I tried to start it Friday night, it would start but would Bog if you tried to go past idle. Almost sounded like it is running on one cylinder. So I changed the plugs (going for the easy fix first) both plugs were wet and black. New plugs didn't help. Next tried to see if I could figure out which cylinder wasn't running. Pulled plug wire first on recoil side and then on the clutch side, no difference, so it will run on one cylinder on either side. Let it run on idle for a little bit and the clutch side cylinder did not seem to get warm. Both cylinders test at 120 psi. Could this all be related to the warm and humid weather or am I looking at something else? New to John Deere sleds (although I learned to ride on a Spitfire about 25 years ago...). Any thoughts??? Thanks in advance for any help!
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ICCSF 108
- Posts: 4369
- Joined: Sun Jul 17, 2005 12:00 am
- Real Name: Kenny Heins, AKA Grumpy
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79 Spitfire not making power
Very well could be the warmer weather, But to make sure that's all it was, I would take the carb off & clean it, Dis-assemble completely & either soak or use spray carb cleaner, also paying good attention to the pilot jet & all the orifices in the carb
( spraying carb cleaner into all the orifices, watch out not to spray into your eyes ) make sure when re-assembling the carb that the float arm is properly adjusted & needle & seat are working properly.. If the carb has a external choke cable make sure that you have the proper play in the cable at the carb.
I like to use at least 2 fuel filters on single carb models, & 3 on twin carb models, ( one before the fuel pump & one between the fuel pump & the carb )
Kenny
( spraying carb cleaner into all the orifices, watch out not to spray into your eyes ) make sure when re-assembling the carb that the float arm is properly adjusted & needle & seat are working properly.. If the carb has a external choke cable make sure that you have the proper play in the cable at the carb.
I like to use at least 2 fuel filters on single carb models, & 3 on twin carb models, ( one before the fuel pump & one between the fuel pump & the carb )
Kenny
Last edited by ICCSF 108 on Mon Dec 29, 2008 3:52 am, edited 1 time in total.
AKA: Kenny, Grumpy, Mr. Richard Head
"I Hunt For it, Purchase it, Haul it, Sometimes Repair it, Sometimes Break it, Then Fix it Again, Label it, Warehouse it, Talk About it, So NOW, HOW Can I Take Any Less $$ For It?"
"God I love the smell of KLOTZ in the morning, That smell, you know that Gasoline/Oil Smell, MAKES the whole place SMELL like.. LIKE VICTORY. You know someday the 2 strokers are gonna end..."
Do Anti-War Protesters have reunions? If so what do they TALK about?
"I Hunt For it, Purchase it, Haul it, Sometimes Repair it, Sometimes Break it, Then Fix it Again, Label it, Warehouse it, Talk About it, So NOW, HOW Can I Take Any Less $$ For It?"
"God I love the smell of KLOTZ in the morning, That smell, you know that Gasoline/Oil Smell, MAKES the whole place SMELL like.. LIKE VICTORY. You know someday the 2 strokers are gonna end..."
Do Anti-War Protesters have reunions? If so what do they TALK about?
79 Spitfire not making power
Thanks for the advice on the carb. Looks like that was the right direction, after getting it into the garage and some light on the subject, first thing I noticed was the fuel line into the fuel pump seemed to have a not so nice hole, so replaced the fuel line. Took the carb out and all apart and cleaned that all up. Was pretty dirty in the bowl and around the main jet. The interesting thing was that when I tried to take off the screw that holds the whole main jet assembly together it broke free and then got real tight. Knowing I did not have any parts to replace that if I inevitably stripped it, I decided to leave it. Anyone have any thoughts on why that may be stuck, would have liked to get that jet out and cleaned it up fully as well.
Anyway, put everything back together and it runs again. Need to do some fine tuning on the idle. Also on the top end, seemed like the motor wanted to develop some more power, I suspect that may be related to the main jet issue. Not sure how to resolve that as I am a little worried about forcing something to try and get it apart knowing that their are not a lot of spare carb parts around anymore...
Anyway, put everything back together and it runs again. Need to do some fine tuning on the idle. Also on the top end, seemed like the motor wanted to develop some more power, I suspect that may be related to the main jet issue. Not sure how to resolve that as I am a little worried about forcing something to try and get it apart knowing that their are not a lot of spare carb parts around anymore...
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ICCSF 108
- Posts: 4369
- Joined: Sun Jul 17, 2005 12:00 am
- Real Name: Kenny Heins, AKA Grumpy
- Location: Blue Springs Mo.
- Contact:
79 Spitfire not making power
Never mind I just figured out that your sled has the B34/32-2 Butterfly Mikuni Carb on it, & I don't have any experience with that carb..
Sorry
Kenny
PS: I would recommend purchasing a JD Blue Covered, Fine Tune Manual 79-83 Snowmobiles, Horicon Works, SP-509-H2 these have a lot of info on carbs, clutches etc. they are on ebay from time to time..
Sorry
Kenny
PS: I would recommend purchasing a JD Blue Covered, Fine Tune Manual 79-83 Snowmobiles, Horicon Works, SP-509-H2 these have a lot of info on carbs, clutches etc. they are on ebay from time to time..
Last edited by ICCSF 108 on Tue Dec 30, 2008 1:03 am, edited 1 time in total.
AKA: Kenny, Grumpy, Mr. Richard Head
"I Hunt For it, Purchase it, Haul it, Sometimes Repair it, Sometimes Break it, Then Fix it Again, Label it, Warehouse it, Talk About it, So NOW, HOW Can I Take Any Less $$ For It?"
"God I love the smell of KLOTZ in the morning, That smell, you know that Gasoline/Oil Smell, MAKES the whole place SMELL like.. LIKE VICTORY. You know someday the 2 strokers are gonna end..."
Do Anti-War Protesters have reunions? If so what do they TALK about?
"I Hunt For it, Purchase it, Haul it, Sometimes Repair it, Sometimes Break it, Then Fix it Again, Label it, Warehouse it, Talk About it, So NOW, HOW Can I Take Any Less $$ For It?"
"God I love the smell of KLOTZ in the morning, That smell, you know that Gasoline/Oil Smell, MAKES the whole place SMELL like.. LIKE VICTORY. You know someday the 2 strokers are gonna end..."
Do Anti-War Protesters have reunions? If so what do they TALK about?
79 Spitfire not making power
Thanks Kenny, I will start looking for one of those manuals. I may head down running something "non stock", until I can find another one of these. Any recommendations on another Mikuni? Would any 28mm round slide work? I noticed that what was used back on many other 340 sleds in the late 70's early 80' (like arctic cat jag, etc).
Thoughts???
Thanks,
Steve
Thoughts???
Thanks,
Steve