MF 135 Engine Starts Missing After Running For Awhile

[ArcherXC]

I have a 1965 MF 135 with the Continental Z145 engine. It has been giving me fits trying to figure out why it runs well for about hour then starts missing so badly I have to shut it down. It still has all the original equipment on it (Generator, original gauges, etc.). I have even moved to running ethanol free fuel to see if that would help.

I have done the following maintenance on it over the last year...

- Changed the coil
- Set timing
- Changed the regulator
- Worked on distributor
- Changed spark plugs
- New battery
- Rebuilt carb
- Had starter rebuilt
- Generator rebuilt

It doesn't seem to be heating up, at least the temp gauge shows normal range. I may need to check that gauge to make sure (by the way, what's the easiest way to check to see if temp gauge is reading correctly?).

Any ideas on why it would run great and then start missing?

 

[BobG_in_VA]

Couple of questions: Are you the original owner/second/third/ owner? (I reason I asked is do you know the whole history of the engine work that has been done on the Z145? Second: Reasoning for the the first question....does the engine have the original heat shield over the carb/exhaust manifold between it and the gas tank?? If its missing the heat can cause the gas in the tank to "boil" and cause severe vapor lock in the engine....BobG in VA

 

[Eagleview]

I have a 1965 MF 135 with the Continental Z145 engine. It has been giving me fits trying to figure out why it runs well for about hour then starts missing so badly I have to shut it down. It still has all the original equipment on it (Generator, original gauges, etc.). I have even moved to running ethanol free fuel to see if that would help.

I have done the following maintenance on it over the last year...

- Changed the coil
- Set timing
- Changed the regulator
- Worked on distributor
- Changed spark plugs
- New battery
- Rebuilt carb
- Had starter rebuilt
- Generator rebuilt

It doesn't seem to be heating up, at least the temp gauge shows normal range. I may need to check that gauge to make sure (by the way, what's the easiest way to check to see if temp gauge is reading correctly?).

Any ideas on why it would run great and then start missing?

Did you change the Capacitor in the Distributor ?

Is the coil you are using an internal resistor type or external ?

 

[klancf51]

I have a 1965 MF 135 with the Continental Z145 engine. It has been giving me fits trying to figure out why it runs well for about hour then starts missing so badly I have to shut it down. It still has all the original equipment on it (Generator, original gauges, etc.). I have even moved to running ethanol free fuel to see if that would help.

I have done the following maintenance on it over the last year...

- Changed the coil
- Set timing
- Changed the regulator
- Worked on distributor
- Changed spark plugs
- New battery
- Rebuilt carb
- Had starter rebuilt
- Generator rebuilt

It doesn't seem to be heating up, at least the temp gauge shows normal range. I may need to check that gauge to make sure (by the way, what's the easiest way to check to see if temp gauge is reading correctly?).

Any ideas on why it would run great and then start missing?

Sediment may be slowly collecting at the outlet in the bottom of the fuel tank. As the gas flows the sediment eventually becomes a noticeable restriction to flow. When the gas flow stops for a while, the sediment separates until the next time. You might try checking/cleaning the fuel tank.

 

[BobG_in_VA]

Personally, I don't think the OP is ever coming back to let us know what's going on.....he posted almost 2 months ago and hasn't made the effort to respond to any posts....OP: If you want an answer, please let us know that you actually still exist....BobG in VA....