Sputtering, threatining to stall.

[Azrael]

Alright, so I have a 2F swapped into a '72, with a rebuilt Weber (not sure which). I'm losing power under acceleration. The engine runs OK at idle, but not great, since I still haven't got the carb tuned fully yet. It get's an occasional sputter at cruising speed, but not too much.

From everything I've found here, it sounds like it's probably a fuel supply issue, but I want to rule out every simple option before putting out cash for a new pump. Since this started last week, I've replaced the filter, and cleaned out the tank (even though there didn't seem to be any problems when I took out the sender and peeked in). I've also verified that there don't seem to be any clogs in the lines.

Anything else I should look into before ordering a pump? Anything else that could be the problem?

 

[3doghouse]

You might want to borrow a fuel pressure gauge before ordering any parts.

It is hard to set up a Weber if pressure is too high, but I would suspect carb setup before fuel delivery problem. It's probably not too low, but you need to measure to know.

There are a probably few Mudders in Denver that could save you some time, money, and aggravation if you can get them to take a look.

 

[fjatheart]

The pump and the correct pressure is my vote to have checked out first. I had a similar problem after running the tank too low and picking up some trash that made it past the filter.

I run an electric fuel pump with two filters, one before the pump and one after. No pressure regulator on my set-up.

 

[Azrael]

Put in an inline pressure gauge today. The pump's putting about a constant 2.5-3 psi. That seems to be about right from what I've seen here, correct?

Also, as I was testing it this time, I noticed a backfire through the carb.

What else could it be, and how do I go about testing/fixing it?

 

[3doghouse]

I would make sure timing and valves are adjusted properly, then focus on jetting:

https://forum.ih8mud.com/40-55-series-tech/213147-***weber-carb***-adjustment-thread.html

 

[Azrael]

I've figured out my accelerator pump is probably bad, with advice from the Rising Sun folks, so I'll be ordering a rebuild kit and doing that again. I've also come to find that the vacuum line on the distributor came to an abrupt end down below the battery box, so I need to find a place to hook that up. After that, I can hopefully focus on adjustments and jetting (or rejet during the rebuild). I don't see any vacuum port coming off the Weber, though. Anyone know where one should be, or if it even has one?

Also, the 32/36 and 38/38 seem to look the same, any easy way to identify them so I can order the right rebuild kit?