1974 300 w/ mikuni

[Waterboy7]

Hey there! I'm currently in the final stages of finishing my '74 300 w/ a 295 Kohler twin. I converted the carb from a Walbro to a mikuni but I'm still messing around with main & pilot jets. Was wondering if anyone else has done this or has any tips for the jetting? Thanks, Rylie.

[JDT]

Might be confussing to set it up with the temps as they are in the summer.

Maybe use jets from another brand with a Mic on a 300 cc engine and go from there when the snow hits.

[Waterboy7]

Yup! That's what I'm planning on doing, just wanted a size reference to go off of before that point. I'm thinking around 200 for the main and 30 or so for the pilot? If anyone else has any suggestions for the sizes, just let me know! And thanks Todd!

[big jeff]

Waterboy what size carb did you go with and what jets did you use ? I am doing the same thing now. Thanks Jeff

[Waterboy7]

Well I figured I should do a quick update on the sled! So far I have her running with a vm32 mikuni, 210 main and 25 pilot... But now I've noticed a leak by the recoil so it's time for crank seals

[big jeff]

hope all goes well . Its so sweet when you pull on that rope and she pops off running for the first time( because nothing runs like a Deere)

[Waterboy7]

Just finished the seals tonight and got her running again. Couple of things that I have some questions about... 1) when I have the engine running for a while and get it "hot" I'll turn it off for about 15 seconds or so and try to start it again.. Its a (bad word) to get started again once its hot. Once I have it going though, it runs awesome. Would that be to a sticky advance for the timing?? The timing seems a little advanced when it's running too, like I'll need to retard it a little bit. 2) why is my exhaust system spitting "unburnt gas" out all over the belly pan? I'll post some pics to explain what I'm talking about!

[Waterboy7]

it appears that the old seal was rubbing against the bearing...

[Waterboy7]

And here is the new one!

[Waterboy7]

And thanks to some helpful info from "bigjeff" I got her put back together and running.

[Waterboy7]

So here's that unburnt stuff I was talking about..

any idea what causes that or what that's indicating?

[big jeff]

Rylie she looks nice I'm jealous of your shop looks like my dream shop lots of room . When I get a chance Ill post some pictures of my 300. Jeff

[Waterboy7]

Thanks Jeff! We'll since no one has picked apart my sled from the pics yet, I'll point out some problems lol. One thing I realized about 2 months ago was that I have the front shocks mounted wrong.. They're on the outside now, and should be the other way around

And thanks for the compliment on the shop! Wish it was actually mine, but that's the perk for working for a water/wastewater municipality

[Matt]

Just finished the seals tonight and got her running again. Couple of things that I have some questions about... 1) when I have the engine running for a while and get it "hot" I'll turn it off for about 15 seconds or so and try to start it again.. Its a (bad word) to get started again once its hot. Once I have it going though, it runs awesome. Would that be to a sticky advance for the timing?? The timing seems a little advanced when it's running too, like I'll need to retard it a little bit. 2) why is my exhaust system spitting "unburnt gas" out all over the belly pan? I'll post some pics to explain what I'm talking about!

Check your plugs after you shut it off, see if they are soaking wet. The excess oil/gas at the exhaust is also a sign of it running too rich.

[Waterboy7]

Will do! Thanks Matt!