Help with Kohler 2 stroke Carb

[ChrisMcD]

Hello All, this is my first post so let me say hello first off....my Name is Chris....I have a nice 197? 6x6 Argo odg that I bought from an older gentleman. The engine was removed and needed to be reinstalled. He said it was running before he removed the engine. It is a Kohler 399cc 2 stroke and I believe the carb that came on it is the wrong one. It is a tillotson HR7A, there is a pulse line out of the engine but no place to attach it to the carb....also there are two fuel lines, I am guessing a return and a feed however there is only 1 in take port....here are some pics maybe someone can help out with some things we can try....thanks

[amphibious drew]

Welcome. First, let me say, I'm not a 2-stroke guy nor am I familiar with your engine, however, the pulse line should be run to a fuel pump as well as the fuel line, then to the carb. My best guess as to having to fuel lines is one could have been an oil line for 2-stroke oil. I've always opted to mix my own gas even when a machine could mix for me. No risk in the oil pump going bad this way. Here is a link to a pdf of the manuel http://www.asberry.net/files/TwoStrokeSM.pdf Its gotta be better than me guessing.

[Don]

Nice looking old Argo.

The Tillotson gets it's pulse pressure from a port in the intake manifold. When the carburetor is off, see if there's a small hole in the casting of the manifold around the outside. There will be a corresponding hole in the base of the carb. If there's no hole in the manifold, I don't see an easy way to use this carburetor. The HR sometimes uses a return line to the tank, but I've also seen them without, so possibly the original used one and this one doesn't.

Good Luck.

[jerseybigfoot]

Sorry Wrong carb. Not worth converting as the Hr7a is for a much smaller engine. This one is more appropriate
Vintage Tillotson HR144B Ski Doo Snowmobile Carburetor: eBay Motors (item 360270444341 end time Aug-07-10 10:06:05 PDT)

[greggv2007]

The carb you have does not have a fuel pump built in, only a metering diaphram. To get this carb to work, you will have to install a fuel pump.

[jerseybigfoot]

The carb you have does not have a fuel pump built in, only a metering diaphram. To get this carb to work, you will have to install a fuel pump.

Actually the Hr7a has a pump in the first stage but it's small and the pulse line is directly connected to a small hole Don described that communicates to the crankcase. These are typically found on old single cylinder snowmobile engines. This carb has a very small main jet check under a welch plug that does not flow much fuel. I attempted to run a converted Hr7a on my 290 cc twin and it could not get the engine up to speed even with the main fuel adjustment unscrewed 5 turns. I replaced the body with a Hr35? in the engine performed much better.

[jerseybigfoot]

Here is a link for some early Ski-doo tillotson applications. I think you should be looking for a HR134A or a HR135A
Engine/Carb Data

[Don]

I'm not as familiar with Tillotson as I am with others (obviously) or I may have caught the thing being too small. I think the HR7A is what came on the Attex ST300D on a JLO 297 single. Personally, I'd block off the return line and find a Mikuni 34 or 36mm round-slide. Not as much tinkering and no diaphram kits!

[jerseybigfoot]

The VM Mikuni would be a good carb but you will have to make up a new manifold adaptor to go horizontal. A Mikuni Seadoo carb is vertical and may work but that would take allot of trial and error.

[Don]

Shoot. That's right. May as well get a bigger Tillotson and a box of kits.

[hydromike]

This won't help a great deal, but the JLO single to (flanged) Mikuni adaptors are out there. I had an Attex ST/295 (the one from Grand Island, Don) that had a VM32 on it. I don't recall what was special about the adaptor, and it wasn't something that was home-made or rigged. I don't know if it was a JLO or a Mikuni part, but they're out there. The 295 ran great with it.

~m

[jerseybigfoot]

It looks to me there is a clearance issue with the transmission and he's stuck with the tilly.

[ChrisMcD]

I had a rebuild sent to me and went with an HR 139A three line....

Looks like it may have 4 lines though so I am not sure what to plug in where? Anyone have any ideas? Here are some pics.....

[ChrisMcD]

Ok the new carb works and my baby runs!! New problem now though....it is sending WAY to much fuel to the engine!! How do I reduce the fuel amount sent to the engine? Thanks

[jerseybigfoot]

what do you have the needle valves set at?