295/s runs bad

[bobcatcharlieboy]

hi everyone firstime on this forum seems like a great site


heres what we got a 295/s that my dad owned since 75 its pretty rough but usable and he loves it

it hasn't been run in about 10 yrs but hes been trying to get it goin for about 2

new cdi ,new coils ,different carbs, new seals, different fuel pump, 125 psi both sides

what it does it seems to spit fuel through the carbs an occasional backfire through either end

it won't turn high rpms maybe 5000 and will sometimes die when you hold the throttle steady

the whole shop will fill with smoke in about 30 seconds when you run it

it leak a small amount of unburned fuel through the exhaust yet runs better when you choke it

sometimes starts easy sometimes difficult surface gap plugs are difficult to read so I tried a different set and they seemed to be burning a little rich but not black just deep brown

Ive tried unplugging the accesory plug no change, but when you run with it plugged in and you turn the light on the tach changes 1500rpm not the engine just the tach reading

Ive tried with the belt off to see if it was something in the drivetrain it ran better but not much also the track turns easily not like something it bound up

sorry for the long post but I'd like to get him back running

after all it is the year of the deere

[400brian]

I'd guess that the stator may be the issue. HewTech has rewound ones.
The instructions for testing the stator is in the FAQs.

Hope this helps

[bobcatcharlieboy]

ty I will test it and see

[HoosierDeereMan]

Another thing is I would toss those surface gap plugs. Even when new the Prestolite ignition systems had trouble firing them. I'd replace them with the regular "J" style spark plug.

You mentioned replacing the carbs. What was the issue with the original carburetors? If the new carbs you installed aren't jetted to 295/s specs that could also play a big part in your problem.

Troy

[bobcatcharlieboy]

just changed the carbs to see if it made a difference same # pilots, mains, needle, and oringinal slides

I did try different plugs not sure what a standard plug equivelent of a bue is I tried a b8hs

[HoosierDeereMan]

Did you get a chance to check your stator? If the stator tested good you are back to the CDI box. Popping back through the carb and only running up to 5,000 RPM sure sounds like a bad CDI box. You mentioned you replaced the CDI once. Is it a know good unit that was working on another sled? I've had one nos that was bad. If you know the box is good start looking at wiring. Check and clean all your connections. Make sure you have a good ground.

Troy

[HoosierDeereMan]

I did some checking and you installed the wrong plug. The reach is too short. It's way up in the head out of the combustion chamber. I've attached a picture to show you the difference in the reach. Left is a NGK BR9ES, center is NGK B8HS, right is a Champion N-19V surface gap.

Troy

[bobcatcharlieboy]

what plug is the proper one to use other than the surface gap plug I didnt want to use a b8hs style because I wasn't sure if it would be too long and possibly hit the piston but if there is no possibility of that I'd try the right plug

[bobcatcharlieboy]

also I pulled the flywheel off to have a look inside and the coil was one that i'm unfamiliar with I'm used to a stator with two coil one for lighting and one 2 stage coil for ignition this one looked like one circular coil

[400brian]

You are looking at the Prestolite CDI system. The stator has 12 poles. 3 are the ignition, the other 9 are the lighting. The ignition poles have two sets of windings, Low RPM and high RPM.
Often the laquer has degraded, and the steel core has rusted, and the windings have shorted or grounded.

[DLDeere]

NGK is BR9ES.

BR8ES will work in a pinch but the cooler 9 is correct.

[bobcatcharlieboy]

after a short break on working on this sled we got back to it this week and I have new info

started it up ran ok but only on the mag side pull the cap on the pto side no change

switched coil wires problem switched sides no brainer bad coil

popped a different coil on, left the coil that was good on and the cylinder that it was hooked to wouldn't fire only the cylinder with the different coil

switched coil wires and cylinders and the problem switched sides

after messing with it for a while here is what I found

occasionally it would run for a few seconds on both judging by the sound of the engine and occasionally it would switch sides that it was running on still only running on one side but aternate sides after 30 or so seconds and then back and forth also it seemed to switch sides depending on rpm low rpm mag side worked high rpm pto side worked

we had inline spark testers hooked up and neither side ever lost or appeared to have an intermittent spark

when the cap was pulled on the side that wasn't fireing ( absolutelynochange to the running of the engine) there was still plenty of spark to the plug



in a nutshell the sled runs fine on both cylinders but only one at a time

[Matt]

I'd guess bad CDI box. Did you ever test the stator as mentioned above?

[DLDeere]

Are you having fun yet?

[lwb140]

ive got a 78 lf that runs the exact same way maybe you will be more persistant than me to figure out the problem , i cant remember details cz its been a year since ive fooled with it but the only thing i have nt changed out are the crank seals and the stator / timing ring .i resolved that the problem had to be crank seal issues . it runs exactly as you discribed and ive done pretty much as youve discribed to fix still runs poorly