Kart Repair – Tillotson Carburetor

In preparation for Race 6 at Englishtown Raceway Park club racing, I had to repair my kart from the issues that I experienced in race 5.  If you read this post, you will see that I had broken my carburetor, the very friendly guys there tried to help me get back out onto the track but it just wasn’t meant to be.  So the carburetor still needed repair.

I had purchased a new carburetor, a Tillotson 395A (the replacement for the HL-166), as well as the repair parts for the original carburetor.  Here’s how I had to go about replacing the carb.

The first, and probably easiest thing that needs to be done, is to remove the airbox.  It is just a screw clam holding it onto the carburetor, if you have any zip ties holding it in place they will need to be removed as well.

PRD Airbox clamp

The next order of business is to physically disconnect the carburetor from the engine.  There are 2 10mm bolts that hold it in place.  You will need a small little wrench to get in there and loosen them but it is doable.  It is a little tricky removing the carb, you need to loosen the bolts all the way to the tips of the studs and then slide the carburetor to the bolts.  You will then be able to loosen the bolts the rest of the way and remove the carb.

This is one of the bolts

This is one of the bolts

This is the other

This is the other

Slide the Carb forward so you can loosen the bolts all the way and remove them.

Slide the Carb forward so you can loosen the bolts all the way and remove them.

The throttle cable stay assembly is next.  You will need to loosen the 10mm (they were 10mm on my kart, they may be different on yours!) guides that hold the cable in place.

Kart Throttle linkage Assembly

Then I had to remove the screw that holds the throttle cable and remove the spring and other side of the assembly.  At this point the whole thing just comes apart.  Be careful not to lose the small little pieces that are bound to go flying with the spring.

Remove this screw, be careful not to lose peices!

Remove this screw, be careful not to lose peices!

Then I removed the air cleaner cup from the front of the carburetor, this is held in place by two allen screws.

Tillotson Air Box Cup

At this point I had removed all the parts that I needed to so I put the old carburetor to the side.

I had purchased a top mount throttle linkage assembly to put on the new carburetor.  This was recommended to me so I went ahead and purchased that with the new carburetor.  In order to use this part, it seems that I needed to swap the linkage around.  To do this, I just undid the screw that held it in place and turned it around 180 degrees.

This piece needs to be pointing where the arrow is to use the top mount throttle linkage assembly.

This piece needs to be pointing where the arrow is to use the top mount throttle linkage assembly.

Loosen this screw and swing the piece around. Use loctite when tightening it back up.

Loosen this screw and swing the piece around. Use loctite when tightening it back up.

The next step was to put the new bracket on.  Remove the two screws on top of the carburetor and install the new bracket with the supplied mounting screws.

Remove these screws

Remove these screws

Use the supplied screws (they are slightly longer) to mount the top mount linkage assembly.

Use the supplied screws (they are slightly longer) to mount the top mount linkage assembly.

Use the new throttle cable guide hardware to mount the throttle cable to the new bracket.  Just slide the throttle cable through the hardware, through the bracket, and then through the hardware on the other side.  Tighten it all up and you should be good.

Thread the throttle cable through the new hardware.

Thread the throttle cable through the new hardware.

Then through the linkage assembly, and through the bottom hardware. Then tighten it up.

Then through the linkage assembly, and through the bottom hardware. Then tighten it up.

The next step is kind of tricky, and I learned how to do it the hard way.  I would recommend that you loosen the throttle cable up by the throttle and give yourself some slack.  I would then fish the throttle cable through the little hole that lets you adjust it on the linkage.  After you put the retaining screw in you will then have to put the retainer on the end of the bracket.  I needed to use the old throttle cable clamp because it had a screw in it to hold the cable in place, none of the supplied new hardware did?  It is easier this way, putting the retainer on the bracket and then trying to fish the line through was impossible.  This is experience talking!

This is what it should look like when it's done!

This is what it should look like when it’s done!

Once you get this accomplished and put the little c-clips in place you can mount the carburetor to the engine.  This part is a pain because it is the opposite of taking it off.  You have to hold the carb close to the end of the studs, slide the bolts on, and then start the bolts.  Once they are started it is pretty simple to tighten them.

The opposite of coming off, look how close the top mount throttle linkage is to the bolt......

The opposite of coming off, look how close the top mount throttle linkage is to the bolt……

HOWEVER……

Be very careful of the new throttle stay assembly.  While tightening the carburetor up to the motor, I broke the same piece that broke on the old carb!  Arghhhh!!!!!   This stuff is fragile so be careful!

That's the part i broke,

That’s the part i broke,

I will not be deterred!  Racing is what I want to do!

So, I took off the new (Broken) carburetor and proceeded to fix the old one.  I used some of the part from the new carb to get it all together and I was able to get it to work.  I used the old throttle linkage assembly with the new pull bracket.  I put some Locktite on the screw and adjusted everything to stop at full throttle when the butterfly is all the way open.  There is a throttle stop on the front of the kart the keeps you from pulling too hard on the linkage and breaking it.  Hopefully I have this set correctly.

Old Carb back on, hopefully working!

Old Carb back on, hopefully working!

This needs to be set correctly so that you don't break that piece that i keep braking. It will stop the throttle cable before the butterfly is fully open.

This needs to be set correctly so that you don’t break that piece that i keep braking. It will stop the throttle cable before the butterfly is fully open.

I am learning that racing is a lot of improvising to get these things working and running.  Sometimes you have to do what you have to do to get out there.  Nothing is perfect, but seat time is important.

 

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