The Poulan engines in that size range are really easy, providing you want to do Gas/Glow or electronic ignition. The 46cc Poulans are a little harder because you have to make some sort of an intake manifold, but the 42cc and smaller versions look like a model airplane engine once you get them all stripped down, without any cutting, grinding, etc.!

Have fun,
AV8TOR

Here's a pic of my B&S 40cc, 4-stroke with the Walbro adapted to it. I used various parts for the spacer/adapter. You can see I have added an external pulse line as suggested by AV8TOR. Also installed a spring from the original WYL carb. in the pump. I have installed a glow plug adapter and an OS A3 plug for starters and will try a gas/glow mix using 30% Heli fuel.

That is pretty much how I did mine. And my spacer tapers from the larger diameter of the carb, down to the slightly smaller diameter of the intake on the engine. Mine works fine with the pulse line that way.

Let us know how yours works out. Can you do a before and after comparison with gasoline, then with the glow fuel added?

AV8T0R

AV8TOR, Didn't know I could run straight gasoline with a glow plug. I'll try it.

Well, actually it doesn't work very well at all. I was thinking you could run it on spark ignition with gasoline before you go to Gas/Glow, just to see how much power the engine gains. Might be too much hassle, I don't know....

AV8TOR

I am hoping to be able to start this engine by flipping the prop. and I couldn't do that with the stock ignition and carb. so I really don't want to go back to that now. Having read some of your other posts in regard to the Honda GX31 or 35 it seems I may not get this to flip start on gas/glow either but I want to try. Once I get it to run I'll see what the RPM's are and try some different prop's. There is another person posting here who has the same engine with the stock ignition and carb. running on straight gas so we can compare notes.

Ok, sounds good. I have an idea that these low compression four strokes are going to really like a dose of nitro; that's why I ask.

AV8TOR

I picked up a quart of 33% Nitro fuel sold by Traxxas called "Top Fuel". It cost $14. It is made by PowerMaster. I'll mix it with some gasoline and see what happens. It says not to use it for aircraft but I asked the hobby shop owner why and he said because it doesn't contain enough oil. That is perfect for what I am doing since the B&S 4-stroke has a wet sump and is better off without any additional oil. Stay tuned.

Well, the engine wants to start now by flipping the prop but it seems to want to start backwards on some flips and throws the prop hub lose. I need a hub that I can use the keyway in the shaft with I guess. I tried locktight and backing a nut up against the hub but it still comes lose after a few attempts and I don't feel it would be safe to let the thing run this way so I have contacted Scott at Brielli to see if he can supply a hub. To be continued.....

Well, I got the prop hub problem resolved after talking with Scott but I have swapped out the carb for a smaller WT with two needles. I also removed the spring from the pump after trying it in the smaller carb. and now the engine is running but I have issues with the throttle. I have to open the throttle a little to get it started and running but when I try to open the throttle more the engine dies. It really seems to be pulling well at only 1/4 throttle. Any suggestions or comments on how to fix the throttle issue is appreciated.

John,
You should start a thread for the 40cc Briggs Gas/Glow conversion.Not that I am such a stickler for staying on thread but I almost missed out on the updates because I had skipped over "carb spacers".Just a suggestion,of course.[8D]

J

Hi J, You are right. As soon as I have this thing running right I'll start a new thread that summarizes what was done. Hope it helps you with your conversions.