Green Machine Rebuild Starts 5-9-16 - Patrollee Help Needed

[r1lark]

Maybe and electric fuel pump in line after the mechanical fuel pump would help. Turn it on when you need it. Off when you don't. Consider it a boost pump. Thats what lots of aircraft have.

Normally an electric fuel pump will be installed as close to the fuel tank as possible.

[r1lark]

Greetings from the High Country,

It turns out that the high high country trails don’t open until late June due to snow. By that time it is hot enough to cause vapor locks after about 45 minutes in low 4. I understand and have returned to Patrolling after cooling the carb with water. However it locks at the worst time or at least when options for stopping on relatively flat ground are a low probability. So I don’t press on into deeper trouble after it restarts I head downhill.

My question is…..knowing the block is cast iron ….how long of a run has anyone had in low 4 after you have cooled the carb bowl? 15 minutes? 30 or longer?

I’m thinking that bowl will quickly reheat from the still hot cast iron block. These trails are legit and I can expect another hour in low 4 uphill to reach the trailhead or destination. Don’t forget a UTV might very well need to get around me on these one track trails while I’m cooling down at a frightening incline.

So if you have experience with the vapor lock cool down cycle please share.

FYI - all vehicles with a carb over exhaust manifold arrangement will have the same problem which includes Jeeps and most other carbureted motors. Why? Cheapest way to build a motor.

Electric fuel pumps help a little, but I like my mechanical ones.

Rolling and Patrolling,
L60Boerne

David, you may want to consider performing a vacuum check on your metal fuel line, to make sure there are no pinhole leaks. Air being sucked in upstream of the mechanical pump can can really hurt the performance of the pump.

[L60Boerne]

Thank you Paul. Would the line not leak if it had a pinhole leak?

[r1lark]

Thank you Paul. Would the line not leak if it had a pinhole leak?

If you see actual drips from the fuel line when the engine is off, it's probably more than a pinhole. A pinhole might make a damp area on the outside of the fuel line. But for a really small hole the surface tension may keep it from leaking out, but when the fuel pump puts a suction on the line air will be pulled in.

Been there, done that, got the tee shirt.................

[timber]

Did you ever figure out why it was vapor locking?

[L60Boerne]

Yes it vapor locks from a combination of altitude and heat. I can run it all day at 5 mph at 4,000 ft in 100 degree heat but at 12,500 ft the boiling temp of water is lower and that is just enough to create a vapor lock which all vehicles with the same carb over exhaust manifold will have. Bad process design but cheapest build path.

[timber]

That makes sense.....

[L60Boerne]

Tom,
I plan to test this out in mid October. If the high country roads are still open I plan to return to 13,000 ft in the white 63. I have made the loop twice in it without a vapor lock when it is around 32 degress F.

The interesting thing is ...is that the motor dies the exact same way whether it is a vapor lock or burned out coil. If I don't get a lesson from Eddie on testing the coil spark I'll have to cool the carb first, which at that temp will not take long, before I can be determine it is the coil.

Rest assured, I will never leave without a back up $18 coil again. I've been so lucky so far.

Rolling and Patrolling,
L60Boerne

[timber]

If the high country roads are still open I plan to return to 13,000 ft in the white 63.

You were in the pinto on the last trip, right? Take some pics and let us know how it goes. Have fun!

Tom

[L60Boerne]

Hey Tim, Check out the stread 06 Ranch and there are few pictures in there. I'll be back out there in a month after Eddie the Eagle beefs up the Red 65. I'll try to post a few more pic, we had some good ones.

Rolling and Patrolling,
L60Boerne