Tuning issues

[Mikel]

Hello,
I'm helping a friend get his M715 running. I have never dealt with the 230 and my carb tuning abilities are very low.

The engine will start, but only with the choke closed or partially closed. It will eventually stall, but starts right up (which contradicts my fuel starvation theory). If I open the choke, engine will not run at all.
Any ideas?
Thanks,
Mikel

[kwai]

How much fuel does the fuel pump move. I disconnect the line from the carb and crank the engine. The pump should fill a small water bottle pretty quickly. Pump pressure is 6-8 psi I think. You can check the TM for that.

will the engine run on something like B12 sprayed in the intake with the choke open. If it does then it just isn't getting enough fuel. I don't use engine starting fluid because it is too volatile.

Have you rebuilt the carb. If not then do that next. If you have did you set the float level correctly. Setting the float level is pretty easy but something often looked over.

Doesn't sound like an electrical problem, but checking the coil (or putting in a new coil) is always a good start. I have had engines that run at idle but won't rev up due to a poor coil.

[hiker]

A vacuum leak like a broken carb base gasket or vacuum line might add to the problem.

I had the same problem with pulling the choke to make the 230 run. Found the carbureator main metering JET size was to small. It was a #58. Through trial and error, worked my way up to a #69 to cure the problem.

see this post: Stock carb main jet size

[Mikel]

Hello,
Looks like we have decent fuel pressure, so I'm pretty sure it's the carb. I can start the engine with starter fluid, and keep it running. But the moment the starter fluid stops, the engine dies.
The fuel bowl had fuel and the accelerator pump does shoot gasoline. We'll be rebuilding the carb tomorrow...
Thank you.
Mikel

[DAVEJ]

If the choke needs to bo pulled out,I would first check for a vacumn leak .