1983 Yamaha Tri Moto 125 runs on spray only

[Faster32]

Just picked up a 1983 Tri Moto 125. First it would start on spray and ran very high idle, like so high you would not want to put in gear.
I checked out the carb and was clean. All jets clear and bowl full of fuel. Now only runs on spray.

Throttle screw on carb was screwed all the way in and the air mixture screw was 6 turns out.
I now have air mixture screw at 1 1/2 turns out.
And Throttle screw turned out a couple.

I am thinking maybe a crank seal bad because of the idling so ungodly high on spray and not able to create a vacuum to pull the fuel from the carb?
I am thinking that as the previous owner might have screwed the throttle screw in all the way to slow the high idle down.

Can anyone help?

[Faster32]

Yes, Starting Fluid.

[onformula1]

Yes, Starting Fluid.

Be careful, starting fluid doesn't contain pre-mix.

I little to test is ok.

If a engine will run on spray, it is usually ignition related, the spray will ignite on a low or intermittent spark.

I would check the fuel system again then a compression test if that's all good go for the leakdown test.

[tborden3035]

Check the carb boot and the reeds. I know the yt175 has a fuel pump on it does the 125 have that also?

[tborden3035]

Also the crank seal on the pull cord side dries out easily and could be cracked.