Tecumseh To The Rescue!

Final pic on the carb conversion. The air filter is installed basking in the beauty of its fresh black lacquer. In actuality this installation is more in keeping and looks more "correct" than the stock setup. Am very happy with the results. The total adjustability of the carb and the ready availability of parts for it are a major plus. Also is a few pics of my latest completion, a Honda bobber built from a beat rusted hulk from St Augustine.
 

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Well I have just had some good luck. We had a generator blow up at work and guess what engine it had..... A Tecumseh!!! Now this was an 8 hp so it might be too big but at least I get to play for free. It does have the idle and high speed jets so as long as the mounting hole spacing is good I get to play. I just bought a cutting board to make the adapter so I'm good to go. woo hoo!
 
It will fit, you will have to elongate the holes slightly. I believe you can get the mixtures in range, about the only thing that may occur is it may(or may not) hesitate on throttle up due to the larger venturi and the momentary stall of the air flow. Who knows, may run perfectly. Cant beat it for free!
 
All the early NE proto-type motors can run on a 26 MM carburetor, and if the carburetor mouth is close it should be possible to tune the carburetor to work well. 26 MM is 1.023" and I doubt the Tecumseh carburetor has a larger opening than 1", therefore it might work well depending on the low speed jetting.

Have fun,
 
The opening is less than an inch but not by much. Well it looks like I can experiment. Very cool!

Jim
 
Both are really nice and look great! I like the lawmower carb conversion.

I thought about that myself, but I don't know enough about carburetors to mess with it. I thought of using a briggs 5hp carb bolted on to a "juice box" for pocketbikes, if it would fit, or using a cheap happytime intake tube with a plate welded on it. Not worth the trouble at this point. I don't want to spend much more on a bike that only goes around 30mph. It works fine now.

I still love to hear about people that tinker with and hot-rod stuff though.

I saw a chainsaw engine on youtube that someone turned into a semi-diesel (glow-plug, like R/c airplane engines) with a flywheel. That might work well for a MB if they work out the mounts and gearing.

cannonball2 said:
Final pic on the carb conversion. The air filter is installed basking in the beauty of its fresh black lacquer. In actuality this installation is more in keeping and looks more "correct" than the stock setup. Am very happy with the results. The total adjustability of the carb and the ready availability of parts for it are a major plus. Also is a few pics of my latest completion, a Honda bobber built from a beat rusted hulk from St Augustine.
Click to expand...
 
For what its worth, I used to do lawn care for a job, and used to mess with cheap and free engines that I got from customers and in trash bins.

I put a 6.5hp B&S carb on a 5hp older Briggs engine, and it would start easy enough. With a jet-ski plug, it would run so hard it would mow 4 foot tall wet grass with a stock blade as fast as you could walk through it, but it was ON/Idle as far as throttle control modulation.
 
What about those old style Briggs or similar carbs that have the attached small tank? They have a feed tube & filter in the bottom of the carb. Can one just cut off the filter and run a conventional fuel line an remote filter?

Thousands of 4hp walmart-special mowers are in abundance, that had a carb which I think mounts on a tube about the size of a Happytime/grubee intake, or uses a ear/faceplate on a similar size tube. Some had self-adjusting start-up chokes and 1 idle/mixture screw. Could these work on a Grubee 49cc?

example of carb and tank http://www.youtube.com/watch?v=OXtxlS5lSuQ
mower used as snow-blower

cannonball2 said:
If you want to run a pumper carb you can easily pick up the needed pulse from the intake runner or the tappet cover. The valve cover is a good place on OHV engines. Hope to finish the conversion today so I can get some time on it to see if it has any issues.
Click to expand...
 
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Basically none of the newer style walk mower carbs have an adjustable idle system. They will fit physically though. The carb with the tank attatched is a form of pumper with the diaphragm between the tank and carb run from the intake pulse in the carb. The earlier versions have slow idle capability, but I dont think would make a good candidate for conversion. Honda carbs have an odd bolt pattern. So the easiest current production carbs to work with are the Briggs Intek horizontal carb(but has a fixed main jet) or the earlier style Tecumsehs with an adjustable main jet. The older Kohler carbs as well as some of the earlier smaller Wisconson carbs are very similar to the original Whizzer carbs, but equally as rare. I am sure there are other viable carbs to consider out there, but the above mentioned are the easiest to lay hands on.
 
cannonball2 said:
It will fit, you will have to elongate the holes slightly. I believe you can get the mixtures in range, about the only thing that may occur is it may(or may not) hesitate on throttle up due to the larger venturi and the momentary stall of the air flow. Who knows, may run perfectly. Cant beat it for free!
Click to expand...

I'm pretty sure it's not too big for my engine. I have a high lift cam and a head that has had some work down to it also. This engine can breath. I elongated the mounting holes this evening so it looks like I will be able to try it this weekend. The weather is supposed to be great too. I'll post my results. This could be very interesting because my Whizzer runs really good now. Sometimes I can't leave well enough alone. lol

Jim
 
Fossil said:
I'm pretty sure it's not too big for my engine. I have a high lift cam and a head that has had some work down to it also. This engine can breath. I elongated the mounting holes this evening so it looks like I will be able to try it this weekend. The weather is supposed to be great too. I'll post my results. This could be very interesting because my Whizzer runs really good now. Sometimes I can't leave well enough alone. lol

Jim
Click to expand...

Well I can vouch for your engine already running great!! I've ridden it & it is fast!! I'm shipping my engine to Quenton today for performance upgrades.
Jay
 
I have not had time to try this carb yet. We here are facing the the eminent loss of a family member. (any time now) I will post my results when I try the carb.
Thanks

Jim
 
OK, ditch the cutting board spacers. Have about 150mi on the Tecumseh conversion, has been running perfectly!. Was shooting off my mouth to a friend with a restored Cushman step thu(1947 I believe) about how my modded motor was running. Wound up in a impromptu race on a country back road. I guess we wound out for 3/4 mi or so with both bikes pretty much equal. We pulled over to let em cool and for me to rub in the fact his Cushman wont run and hide from the Whizzer any more, when I noticed the carb spacer looking a little bubbly. Long story short, the spacer "bonded" itself to the head. Had not had an issue until the long WOT run. Either they have changed the material from my earlier spacers(which are still in use) or the Whizzer is a HOT runner! Believe I will whittle one out of Phenolic! If yall bought any boards give em to the woman in your life for Christmas!
 
Ah!

Been there done that.......

I made special covers for Whizzer USA during original oil flow tests. The plan was to watch the oil when the motor was running. It wasn't long before the Plexiglass melted and had to go to plan "B". The first to melt was the tappet cover, then the side cover started to buckle, but we were able to get the information we were after prior to the failure.

Many shows I attend have rides, most are divided into 2 groups, slow and fast rides. The stock Whizzers and other motorbikes take part in the slow rides. The Cushmans, Powells, Salisburys, and other scooters making up the fast rides. The Cushman guys always hunt me down to ride with the faster group. Most of the time about 6 of the quicker Whizzers end up at the front of the faster crowd. Usually a couple of Whizzer with OHV motors and Gerd Lowack, Kurt Melancon, and myself running the flat head motors [all will easily outpace the Cushmans] above 60 MPH.

Have fun,
 
Yeah my bike is in the 50mph top range. This is a single speed Cushman. He used to kick my butt until I did the mods you laid out in an earlier post. Now he has a new found respect for the the ole Whizzer. BTW I pulled off the cutting board spacer and found it in pretty good shape. The error of my ways was not running the enlarged restrictor plate as a heat shield. I cleaned and reassembled with the restrictor plate. Now I will see if he wants to go again!
 
After logging a little over 100mi with the modded engine with the Tecumseh carb, I have to say I am very pleased. Runs consistantly in the 48-50mph range on top, but where it is really enjoyable is crusing between 35-40. Seems relaxed at these speeds, yet has some pretty good power on tap for hills, and is quite smooth. I was amazed just how lean I had to adjust the carb on the main jet for clean running. Seems to have a little more power with Quentons mushroom lifters, but I also advanced the timing a little more at the same time I installed the lifters(never try 2 things at once if you want to know what made the difference). For any one dealing with the typical Whizzer issues all I can say is persevere and you will be rewarded with a really nice motorbike!
 
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