Carter YS950 choke on 1952 M38A1

MTM38A1 · Post by **MTM38A1** » Mon Oct 17, 2016 5:05 pm

I have cold starting problems. Its 50 degrees out. I have searched and read other posts. I use full choke and no throttle. The choke valve plate is fully closed by visual inspection. Will not start. I cover the carb opening with my hand, feel lots of vacuum, and the jeep immediately starts and runs great thereafter when warm. There is a one way valve in the choke plate that allows air in, which seems to be the problem. With the carb opening totally closed off with my hand, it starts. Just using the choke plate will not allow it to start.
Any suggestions

MTM38A1 · Post by **MTM38A1** » Mon Oct 17, 2016 7:00 pm

I've done more searching. I eliminated the oil bath air filter and replaced it with a 4 inch cone filter. I am thinking now that this has altered the air/fuel mixture and is allowing more air to get to the carb when the choke is on.
Think this is possible?

4x4M38 · Post by **4x4M38** » Mon Oct 17, 2016 8:07 pm

You are saying it runs with no air filter. Replacing the oil bath with an aftermarket should ( and as you show) make no difference.

Re: covering the air horn with your hand.

Sounds like you have an air leak somewhere.

Post by **wesk** » Mon Oct 17, 2016 8:56 pm

I eliminated the oil bath air filter and replaced it with a 4 inch cone filter. I am thinking now that this has altered the air/fuel mixture and is allowing more air to get to the carb when the choke is on.
Think this is possible?

I doubt it. The 4" cone type will pass just as much air as the oil bath. Think on it a bit more.

Your problem is one of two.

1 - To much air
2 - Not enough gas.

1 is going to be down stream of the choke plate. IE: Vacuum leak.
2 is going to be either low float level, clogged fuel passageway or inoperative accelerator pump.

scoutpilot · Post by **scoutpilot** » Tue Oct 18, 2016 4:02 am

Does it start any easier if you apply about half throttle with the choke closed?

oilleaker1 · Post by **oilleaker1** » Tue Oct 18, 2016 4:54 am

Your fuel pump may be down on supply. Check it's delivery volume to the carburator, and fuel pressure. Mine was hard starting with the choke also, and it ended up the fuel pump wasn't up to snuff. John

MTM38A1 · Post by **MTM38A1** » Tue Oct 18, 2016 7:01 am

scoutpilot wrote:Does it start any easier if you apply about half throttle with the choke closed?

No

MTM38A1 · Post by **MTM38A1** » Tue Oct 18, 2016 7:02 am

oilleaker1 wrote:Your fuel pump may be down on supply. Check it's delivery volume to the carburator, and fuel pressure. Mine was hard starting with the choke also, and it ended up the fuel pump wasn't up to snuff. John

I'll check that. I have an electric fuel pump. Thanks