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Treepep

K91 question.

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Treepep

I have a non running, pullstart K 91 that powered a compressor.   Carb is a vacuum pump type at the carb.  In great condition.   New cleaned and adjusted points.  New plug.  Removed the flywheel and cleaned the coil and mag bar.  I still have no spark.  Continuity is solid. Great compression.   I do need all the governor biz.  

 

Thoughts?  

 

 

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wallfish

CLEAN CLEAN points and try adjusting them tighter to .018. Sometimes even tighter as I had one at .016. New points have a coating on them in the package to prevent oxidization.

Personally I haven't ever had an issue with the magnet strength but there have been a couple of guys over the years that have had to change the magnets on the flywheel to get spark.

Condenser maybe

Sometimes the fastest way to get spark is to have @Pullstart hold the plug wire while cranking it! LOL It worked on that old Briggs at the big show!

 

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Treepep

Cleaned sanded and gapped the brand new  points,   plug is new and gapped  appropriately.   all biz under the flywheel is cleaned and adjusted.  re coil biz is great.  No spark

 

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wallfish
28 minutes ago, Treepep said:

gapped the brand new  points

to what size? Did you try shrinking that gap?

As many others here have had and so have I, a new spark plug these days doesn't mean squat. Check the plug on a known working source like a different running engine. Same for a new condenser too

The manual may include a way and the parameters to test the coil with a multi-meter

 

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squonk
12 hours ago, wallfish said:

 

Sometimes the fastest way to get spark is to have @Pullstart hold the plug wire while cranking it! LOL It worked on that old Briggs at the big show!

 

I built a coil tester whilst at Napa. Used and old Chevy distributor to activate the points. One day 2 of my co workers had it out and were going to test a customer's coil. One guy was connecting it and the other was chatting with the customer. All the while not knowingly twirling the dist. gear back and forth while the first guy was connecting the secondary wire. Guy hooking it up kept getting zapped! I just stood back at the other end of the counter and watched with amazement on how long this went on! :hilarious:

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Treepep
13 hours ago, wallfish said:

to what size? .02.  . Did you try shrinking that gap? tried .018 no change

 

As many others here have had and so have I, a new spark plug these days doesn't mean squat. Check the plug on a known working source like a different running engine.

 

Condenser and plug came with it.  tried a new NGK @ .025.  No dice

Same for a new condenser too

The manual may include a way and the parameters to test the coil with a multi-meter

Cleaned the mag strip and ignition coil under the flywheel.   

 

NEW points and she is coughing.  Will run briefly choked.  I cleaned and re installed the carb.  I think I need a new one.  No luck finding a rebuild kit,  I know kits are available for a wh K91.  This carb I have not seen before.  Any links to a complete carb?

13 hours ago, wallfish said:

 

 

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wallfish

You got any pics of that carb?

If you can find or order a carb for a K91-K181 it will fit right on there.

A Clinton carb is another option

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Treepep

This carb is soaking.  I took everything apart.  Cleaned and it sorta ran.  Win...  not getting enough fuel.  A carb with a sediment bowl would be preferable.   

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20250825_152659.jpg

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wallfish
Posted (edited)

I've never seen one of those before but I have a WHOLE BUNCH (60 +) of little 2 stroke engines that use pulse pumped carbs. The diaphragm in there MUST be soft and pliable and no stiffness at all or it can't move to pump fuel from the little amount of pulse pressure. Tank above the carb and clean the check valves good.

Is there anything special with that diaphragm or is simply a piece of rubber? I have some fuel resistant diaphragm material that I can send so you can make one if it's just a simple material set up

Edited by wallfish

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