Hoglet with Howell carburetor

I have completed my Hoglet engine along with the howell 2 jet carburetor. I'm running Coleman fuel with wd 40 added at the rate of 6 oz. per gallon. I've read several (all different) methods of setting up the Howell carb. I made the needles as per the drawing so they are stubbier than other needles I've made in the past, therefore only a small adjustment makes a big difference. 1/4 turn on either needle floods the engine. I can get the engine to idle and it sounds great but cannot get the throttle to respond--UNLESS I cover the vent hole on the gas tank cap. Then the high speed comes in but it quickly dies. The hole in the cap is 3/32 (.09375"). What would be the reason it would rev up when the hole is covered? I've read where Brian drills a .040 hold in the cap, so maybe the size creates a draft effect. I've build the Kerzel and the Webster. The Kerzel has a hole in the cap and the Webster doesn't. Thanks for any help.

Mark

I have no experience with the Howell carb but if your engine is revving then dying when you cover the vent hole in the tank then it is getting too much fuel. The hole in the cap allows air in to replace the fuel used so as a vacuum is not built up. If allowed to build a vacuum in the tank the engine will receive less and less fuel as the vacuum increases until it's not getting enough to run. So what I think is happening is your engine is choking on too much fuel and managing to just stay idling but as you reduce the fuel available the mixture improves to the point it can rev, but then it starves for fuel shortly after as more vacuum is built up in the tank.

If you have 2 mixture needles (which I assume you do from the sounds of it) I would see if you could get the engine running on just idle mixture, with the high speed turned all the way off. Then you can ease the high speed open a tiny bit at a time until it starts responding. I would say at the moment you're running off both needles so essentially they're both in the wrong positions and it will be difficult to work out which way to adjust each needle simultaneously.

I'm also not sure why the tapers would be short and stubby. I prefer my mixture needles to be very gradual tapers so they're not so 'touchy' and easier to set.

As for your other engines, either of them should run without the cap on the tank. As long as the tank is vented then it doesn't matter what size the hole is (within reason of course). I would guess your Webster fuel cap is not sealing around the threads and that's where it's getting it's air from. You could test it by starting it with the cap off then plugging the hole with your finger. Unless it's leaking somewhere else the engine should stop after a short while.

Thanks for your reply. I’ll give these suggestions a try this afternoon. I think I’ll remake the needles also because they’re so touchy. Thanks.

Cogsy, thanks for your input. Yo set me on the right path with with too much fuel. I remade the needles and they made a big difference. The hoglet will idle and rev, but not to the very high rpm. I'm gonna play with it some more. But I am getting a response from the throttle and that's good. Here's a picture of the old and new needles.

That's great news, glad it helped. I'd be interested in a video of the engine running as well - the Hoglet is on my 'to build' list and I always enjoy seeing builds of them.

I'll post a video maybe tomorrow afternoon. I'm currently starting it with a drill. I made some cast iron gears for the kick start but they broke. I'm planning to make some more with brass. The cast iron I used was of poor quality. Also as a side note, I'm a Hoglet head specialist. I cast a lot of blanks that I then mill for parts on my engines. I wound up making 5 heads. I was having a porosity problem with my castings and they wouldn't allow compression. I finally got 2 good ones outta the bunch.

I tried to upload a video but it says not an allowed extension (mov). I converted to mp4 and it says the same. I'll try again after I've figured it out.
Mark

Hi
The best way to post a vid is to upload to your own youtube channel like this
Then post a link

I used the Howell 2 jet carb on my hoglet and struggled a little to begin with but the carb works a treat. I started with the high speed mixture screw fully in and fiddled with the idle mixture screw to find the sweet spot.

I’d then unscrew the high speed mixture screw maybe half a turn, begin to rev the engine and go from there. It’s all trial and error but that’s the best way I found. You can hear the sweet spot as it’ll pick up revs and if you go too far to where it’s flooding the engine it will bog down and die.

You may consider it cheating, but a #18 darning needle makes the best carburetor needle. Is made of hard steel, is shiny, has a slender point and a 0.050" diameter shank. A package of 5 is a couple of bucks.

Well I finally got the video posted. Mauro, I've used them before and they work good. I recently saw a video from Joe Pie where he turned a larger diameter down to a very small diameter in one pass. I used that method with my compound set at an angle to make the needles. This worked great after playing around with it a bit. Neil, your method helped alot. Can't tell it in the video, but it is responding to the throttle better now. Also Neil on your 2 jet carb, did you use viton orings on the throttle shaft? Thanks for all the help.

nice hog build. this is what i wanna build next. thanks

Congratulations on a lovely working engine!
Yes I’ve got as per the drawings 2 viton O rings on the main shaft with the air filter on the front (picture below). It’s a good idea as over time it’ll suck up lots of small dirt which may damage your piston rings. I also run mine on Coleman fuel with a few drops of 2 stroke oil and haven’t had any issues.