'77 440 Liquifire kioritz Problem

Sliquifire · Post by **Sliquifire** » Tue Feb 07, 2006 10:18 pm

I just rebuilt my 1977 Kioritz 440 Liquifire engine with nos Deere parts. My rebuild includes crank seals, all gaskets, pistons & rings. It now starts and idles just fine but it seems like it wants to run mostly on one cylinder when you try and run it down the trail. I had the compression checked at a local shop and both sides are identical at about 140 lbs per side. The shop also checked the spark with a special plug on each side and that also seems to be fine. What I can see as a problem indicator is that when I pull the plugs one plug looks normal and the other side plug (clutch side) looks like its barely firing. The very tip of the plug is brown but the top surface below the tip and plug threads are totaly clean. The shop mechanic that checked the compression said it looked like this side was getting too much gas for the plug to ignite properly. Interestingly enough when I asked the mechanic, who is an old timer, if he would look further into my problem, he said he wouldn't work on John Deeres because he never had any luck fixing them? Ouch! Right now my Liquifire kind of runs like a tractor, please help! Any advise would definitely be appreciated!

buck43 · Post by **buck43** » Tue Feb 07, 2006 10:48 pm

Have you cleaned the carbs?

harleysportster · Post by **harleysportster** » Tue Feb 07, 2006 11:32 pm

Sliquifire,
Did the shop use a clip on spark tester which shows a spark externally.
Alot of times the spark looks good on the outside but under compression, the spark is to weak and fouls out. Do you still have the original cdi box on the engine. Check out the FAQ section on diagnosing the ignition. Also check simple the things :
check/ replace fuel filters
check/clean carbs
check/replace spark plugs

MARK · Post by **MARK** » Wed Feb 08, 2006 12:09 am

Slick,if your thinking it's fuel related switch the carbs around and see if the problem follows the carb???

Sliquifire · Post by **Sliquifire** » Wed Feb 08, 2006 1:36 am

Thanks for your replys, the answers to your reply questions are:

- a clip on plug that showed an external spark was used to test spark.
- carbs have been cleaned and jetted to original specs provided by Harleysportster.
- I did also change the throttle valve slides from 3.0 to 2.0 because of carb spec info.
- sled has original CDI box.
- new fuel filter and gas lines.
- Have not tried switching carbs around yet.
- Have not gone through clutching with a fine tooth comb yet.
- new belt Max 1078
- new plugs NGK B9ES, not sure what gap to use so just used them out of the box. both plugs at about .025

I'll was thinking about going through the carbs again and if need be try switching them around. Any more tips with the above added info are still appreciated, thanks!

harleysportster · Post by **harleysportster** » Wed Feb 08, 2006 1:14 pm

Check this out from the FAQ section.
http://s12.invisionfree.com/jdsleds/index.php?showtopic=491

JDFanPa · Post by **JDFanPa** » Wed Feb 08, 2006 1:35 pm

I think the easiest thing to check is switch the carbs and see if the problem moves like stated by Mark this will be helpful in diagnosing if its a fuel or electric problem. Naturally if the prob cylinder changes you know its the carb somewhere if it doenst move and the compresion is 140 you really need to look into theelectrical side like harley stated

Added Note:: clip on spark testers are junk imho atleast get an inline that goes between the plug and cap the clip on can show spark in the wire when theres none at the plug all because the screw on plug caps can go bad and also the connection where itt goes into wire gets corroded over time

JoeRainville · Post by **JoeRainville** » Thu Feb 09, 2006 12:41 am

Hey Guys,

Here is just a little more to add to this string. Intermittent igntion problems, or ones that show up under hi RPM or load are a pain to find. Sometimes what sparks great cold will die out hot.

For example, Deere put a coil cover (HDA touch?) over the external coils on the 76-78 Liquifire motors. Seems like a bad idea to me, since heat will cause the plastic to break down, and if you overheat the sled, the body of the coil melts.

Aside from switching carbs to check for a fuel problem (a great way to diagnose a fuel problem by the way), try changing the leads on the coils, or switch the external coils from side to side to see if the plug that is not firing well follow the external coil. If that shows nothing, see if you can swap in another CDI box to see if that fixes it. If the carbs, ex. coils and CDI box seem OK, look at the Stator. Deere has a check out proceedure for it, that I think has been posted here before.

Kind of funny, but I've failed one stator on my 99 Cat Sno Pro a few years ago at at race. The Cat mechanic figured it out because changing the external coil didn't fix it. When my 02 Cat Sno Pro had ignition failure at the track, it was the external coil, and my mechanic found it by replacing it first. Not the most scientific methode, but it worked...

Good luck with your Liquifire!
-Joe Rainville

JCG · Post by **JCG** » Fri Feb 10, 2006 4:56 pm

The clutch side sparkplug wire goes through a clip at the top of the head. It is rubber coated but mine still managed to get nicked by the belt guard causing an arc. Had the same problem you had until I noticed the arc. The only advantage to having a low light garage.
Good luck

Sliquifire · Post by **Sliquifire** » Sun Feb 12, 2006 5:17 pm

For what its worth Here's an update on my problem. I switched the carbs over the weekend and now both cylinders are working good! I ran it in an 8 mile relic run on Saturday with relatively no problems, go figure?

Thanks again, everyones advice did help me out!