4A032 Military Gas Engine (12-15 HP) for off-road buggie?

[Steelart99]

It's like a half scale vw engine.lol

More like quarter scale

[Steelart99]

So, I started my testing to see how this engine might work. It is 50 years old and I started it once about 25 years ago and ran it 2 hours, then changed out the oil and re-crated it until yesterday. I installed a 12V BMD 318i starter motor on it and got some ethanol free gas to run the initial tests. Took a little while to get it started, but it did fire up and ran smoothly (noisy - no pipes / mufflers). It has a speed governor on it, so it stayed running at a constant speed of about 3500 rpm; something I might have to remove if I opt to use this in a buggy. Or ... use it to drive a hydraulic pump / hydraulic wheel motors ... a different type of buggy then (I'm thinking too much here ... sigh)

Next step is to take the carb off and bore it out to 9/16" or 5/8" and replace the float with a brass float. I have picked up another old carb that has a suitable float after minor tweaks. That should give me greater HP and the ability to use ethanol gas. If that works out, I have to consider if I want to remove the heads and shave them down to boost the pressure/HP.

[LIDUNO]

Definitely going to have to remove the governor. There would be no sense in using a bigger carb if you didn't.

[Steelart99]

Definitely going to have to remove the governor. There would be no sense in using a bigger carb if you didn't.

+

I absolutely agree ... Unless I opted to try to make a hydraulic driven off road vehicle (skid steer???) ... a set rpm is optimal for driving a hydraulic pump. All that said, I don't think I really want to head down that road.

[LIDUNO]

Never really seen a fast hydraulic wheel vehicle. Probably make a good crawler though, you could be totally independent suspension.

[Steelart99]

So I received the ebay 'donor' carb that I'd been pointed me to. I stripped out the brass float, which was pristine! I tore down the carb on the 4A032-4 engine and its float was an exact match to the donor carb. I did a slight mod on the brass float pivot and it dropped right in. I love when things work out that way. While I had the carb apart, I also opted to drill out the venturi to 9/16". Well the new drill I had 'chattered' somewhat, so I got to spend about an hour with a dremel cleaning up the marks inside and trying to get a more polished finish. Reassembly was a breeze.

Put the carb back on the engine and it fired right up. I did have to remove the governor linkage on the engine and then adjust the idle and running speed.

Success on these mods! Next I will probably try to shave the heads down a bit and get the cylinder pressures balanced.

Gotta see if I can find a performance shop that might be able to do a dyno test on the engine so I can get a true reading of what the HP and Torque are on the modified version.

Pics: 4A032-4 Carb, Old float, Donor Carb, Comparison of floats, Brass float installed

1 4A032-4 Carb.jpg2 4A032-4 Carb Float.jpg3 Donor Carb.jpg4 Both Floats.jpg5 Brass Carb Installed.jpg

[LIDUNO]

Probably could have use a honing stone and cleaned up that carb bore in under a minute. I use to rebuild wheel cylinders back in the day, took no time at all to hone them.

[Steelart99]

Probably could have use a honing stone and cleaned up that carb bore in under a minute. I use to rebuild wheel cylinders back in the day, took no time at all to hone them.

I didn't think of honing stones ... Doh!!! I'm not sure I have circular ones on hand ... Oh well, I got it done; just took a bit longer than planned.

[LIDUNO]

They make them in all different sizes.
https://www.amazon.com/Lisle-10000-B.../dp/B0002SQUG8