Hit and miss engine

[coulsea]

Finished the transporter and mounted the ignition for my latest engine.
Just need to tinker with the hit and miss springs to slow it down, I will run it in a bit more first.

Based on these plans https://www.ebay.com.au/itm/Model-H...836964?hash=item4b449f49a4:g:lvUAAOSw8SpbCS3y

 

[Tom 1948]

Looks good. I have those plans also but not gotten around to building it yet. I take it that you are a pretty experienced builder. I have not been at this very long. What kind of skill level would you rate it at?

 

[coulsea]

Tom, I have built a few steam, flame licker and IC engines over the last five years, but I am still learning and not a perfectionist. The main body and hopper on this engine are fabricated and involve welding, grinding and body filler which takes a fair amount of time. I tend to not follow plans too closely and change things to suit my machinery, materials and skills.

 

[Tom 1948]

Thanks for the reply Coulsea.......Tom

 

[blackangus]

Hi I have built a bits & peace's hit and miss (Philip Duclos) and have it running but I'm having trouble with the fuel control. Built the needle and body to plans but it seems to be hard to consistently set it.
Looks similar to your . Any ideas ?

 

[Tom 1948]

I am far from being an expert on these things but from what I have seen and known homemade carburation is always a problem. You have to usually improvise a choke of sorts to get it rich and as it warms up it may run at a pretty much fixed position. You can get a manufactured commercial carb but none that I know of have a choke or enrichener as some call it. I have a Chinese built hit & miss and it has a needle valve. I use my finger as a choke plate, give it a couple of spins and I then have to block airflow till it can run on its own. If any motor starts without a choke its usually too rich and may tend to foul plugs after warm up .

 

[coulsea]

I use the this carby
https://www.homemodelenginemachinist.com/threads/updated-simple-carburetor-design.29047/
the hole in the fuel metering tube needs to be turned away from the flow of air and it works well.
I have found that inconsistent running is often caused by inconsistent compression which results in inconsistent suction and airflow in the carby, this can be corrected by adjusting the mixture screw until things change again making you think that it is a carby problem. valves are often the problem.

 

[Tom 1948]

I tend to agree with you. That carb looks good and that guy Chuck has built some pretty nice stuff.