ST 350 Main Jet Size

[Blackstone]

Greetings Everyone,
I recently purchased a 2004 ST 350 that wasn't running very well and I suspected the carb. The previous owner installed a cheap after market carb a few years ago and that was in fact the problem. The carb is cracked almost in half right through where the throttle plate shaft goes into the body. I am going to order an OEM from Country Cat but they have two part #s. One with a #86 jet and one with a #90. I am not sure which one I need. What came stock on the pre mci ST350? It is definitely the pre mci motor. It has the separate exhaust manifold and the part # on the timing belt cover is EH35C. Any help would be greatly appreciated.

[trig123]

I ordered a new one last summer from country cat for my workhorse with the pre mci 350 and it was the 90 jet. Runs great. Here is my order that I just copied and pasted.

E-Z-GO OEM Carburetor - Fuji Robin Subaru pre-MCI 350 - 90 Main Jet 72558G01

Someone must have changed that engine because all the 2004's I have seen came with the MCI. No big deal because I also own a 2005 that I converted to the pre-mci engine.

MCI engines have a grey timing cover and of course the exhaust manifold is intergraded with head. Pre Mci are much better in my opinion

Hope my answer helps because it does get confusing on the jet size. Elevation has a factor in choosing jet size. I am assuming where you are located is not above 2000 feet. Tom

[Blackstone]

Thanks Tom. Yes I am just a few hundred feet above sea level here in VA. I was confused at first about the motor as well. I thought that the 2004 would have the mci motor as well. The guy I bought it from is a good friend and he has had it since 2007 and he did not change the motor. So possibly the first owner changed it out. Thanks for the correct Country Cat part# Don.

[trig123]

Originally Posted by Blackstone

Thanks Tom. Yes I am just a few hundred feet above sea level here in VA. I was confused at first about the motor as well. I thought that the 2004 would have the mci motor as well. The guy I bought it from is a good friend and he has had it since 2007 and he did not change the motor. So possibly the first owner changed it out. Thanks for the correct Country Cat part# Don.

You welcome. 2004 was the first year they went to the MCI and now that I think about it I have seen more than once things like yours.

I am sure yours came with the pre mci.

I actually once owned a 2002 ezgo txt and it had the old style steering. It was for sure a 2002 but according to the manuals it would have had the steering rack on top of axle. It didn't.

Just one of those things when they change from one thing to another on these carts. Good luck with your cart. Tom

[Blackstone]

Tom,
I have found a bit more information on the jet size. Apparently the #86 jet was used with the round style air filter and the 90 was for the flat filter. I have a round filter and Country Cat is out of stock on the 72558G03. But they have the 72558G01 which is the #90 jet. Do you think I could just swap out the jet and be ok? From what Ive read the airflow is different for the flat and round filters hence the different jet sizes. And where could I get a #86 jet that fits? Thanks. Don

[trig123]

Originally Posted by Blackstone

Tom,
I have found a bit more information on the jet size. Apparently the #86 jet was used with the round style air filter and the 90 was for the flat filter. I have a round filter and Country Cat is out of stock on the 72558G03. But they have the 72558G01 which is the #90 jet. Do you think I could just swap out the jet and be ok? From what Ive read the airflow is different for the flat and round filters hence the different jet sizes. And where could I get a #86 jet that fits? Thanks. Don

I really can't say on that. I sure wouldn't want to start changing jets on a brand new carburetor . Not sure where to get the #86 jet.

Also this is the first time I ever heard about air cleaners making a difference in jets.
I was thinking the round ones came with the MCI engines but it has been 10 years since I last worked at a golf course that had both Pre and MCI engine. Sorry I couldn't be of more help. All I know I put the #90 jet in my 350 and it runs great.
Tom

[Blackstone]

Tom
I ordered the 72558-G01 from Country Cat. They did give me an EZGO part # for the #86 jet. I was able to order it directly from EZGO. I am going to install the carb with the factory jet and see how it runs. It if seems to be running rich I will drop the smaller jet in. Do you have a round or square filter on your cart? I appreciate all the help Tom.

[trig123]

Originally Posted by Blackstone

Tom
I ordered the 72558-G01 from Country Cat. They did give me an EZGO part # for the #86 jet. I was able to order it directly from EZGO. I am going to install the carb with the factory jet and see how it runs. It if seems to be running rich I will drop the smaller jet in. Do you have a round or square filter on your cart? I appreciate all the help Tom.

Square filter on mine or I might call it rectangle .

I also have a 2005 workhorse that I converted to the 295 Pre Mci a few years ago and its got the round one on it.

When I bought it the original 350 MCI had a large hole in side of block so being I had this 295 pre mci and wiring plus all igniton parts that's what I put in it.
My wife uses it and she can't tell the difference in which motor is in there

I installed a new OEM carburetor on it and it was a MCI. I found a bargain and it worked out fine. I don't have a clue what jet is in it but it runs good.

You can tell a MCI from a Pre MCI by looking at the throttle plate. MCI has 13 stamped on it and pre mci has 15 which stands for 13 and 15 mm.

That's the size of the venturi . Also that is a good way to tell if your carb is OEM or aftermarket cheap 0. No numbers on the cheap ones I have seen and OEM do have the number stamped in it.

Not sure you saw this on this website, if not here is some info about the updated MCI engine. They do crank much better but I still like the pre mci's better.
Tom