Rough Idliing

[Chip Sandage]

I'm continuing to experience rough idling with the M-37. It seems to occur after the M-37 has been driven for about 20 miles. The last time it happened was driving home from a car show.. The M will run rough if I don't keep it at a fast idle. I've replaced the needle and seat. There are air bubbles occasionally between the fuel pump and fuel filter. The last incident happened late in the afternoon and it was not a excessively hot day. This same issue happened at the rally too. I'm thinking it's more than vapor lock. Perhaps a fuel pump problem?

[Matthew Welcher PWA]

Chip, check out the linkage going to and from the carburetor, see if something seems off there. The next thing I can think of is a vacuum leak, Check all of your vacuum connections going to and from your wiper motors and intake manifold. See if something hasn't popped off from where it should be. After that try spraying a little carburetor cleaner around the base of the air cleaner, see if you get anything from that point.

[Chip Sandage]

Thank you Matt. I'll try that this weekend. The wipers seem to operate intermittently, figured that was the nature of vacuum wipers. Perhaps not. I have an 24 volt electric pump, regulator and a fuel pressure gauge. What do you think about bypassing the mechanical pump all together? I also have a SPDT oil pressure switch to cut off the pump when the motor quits.

[Matthew Welcher PWA]

Chip there is nothing wrong with going to electric on your fuel pump, the regulator and pressure switch are fantastic ideas. Remember to get the pump as close to the tank as you can. And I would say try setting the pressure regulator at around 4 psi or so to start and see what happens. To switch to electric and putting a block off plate where the stock pump was requires re routing of the vacuum lines to the wipers.

There is a port at the rear of the intake manifold at the top that works great to attach a fitting to to run your vacuum wipers. Please keep us up to date on how the old girl is running.