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Not looking to start a brand name war but

1041 Views 3 Replies 3 Participants Last post by  Chipmaker
Just what differences are there with Tecumseh and B&S engines. I did notice there is a big weight difference, between the two brands of smae HP and engine type catagories.

My reason is this: I built a gas powered string trimmer (push type). It has a 110702 model engine of 4hp on it. I originally thought it was a 3 1/2hp but its a 4. While the engine runs great when its running, its just hard to get started. The motor was originally on a push mower, and now it does not have a blade for kinetic energy, and this is causing problems in starting it.

I am told I need a heavy flywheel type motor such as used on tillers or pressure washers etc (things tghat do not have a large rotating mass so I am going to have to buy me an enginem and I am having problems deciding between tecumseh and briggs. So will say a 5 or 6hp engine fit in the same foot print as the 4 I already have on it? The 4 has plenty of power, but there are some at higher hp at lower prices. I need a vertical shaft, with 7/8" crankend, and a 3/16" keyway slot, and preferably with remote operating control.

Any suggestions as to model / brand etc would be appreciated, as where you can get the best prices. I know about Tulsa small engines, and the small engine warehouse. Tulsa is higher but they appear to sell mostly brand new currrent production, we as Small engine warehouse has a ton of Scratch and dent and no real true description is given, not even a photo of the engine, so I am kind of leary dealing there.

Any suggestions appreciated.
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I have mostly Tecumsah engines on my non-JD equipment and have found them pretty reliable. The only B&S engine I have is on my 8HP rototiller. It has become harder to start in the past year or so but it could be it needs a carburetor rebuild which I will have done next season. My only observation is that the carburetor on the B&S needs more adjustment than on any of my Tecumsah powered equipment to run smoothly. Other than that, both have been good engines for equipment that I don't use that often. I have an Ariens 6HP string trimmer mower with a Tecumsah that has been easy to start and performed very well with no maintenance for the 3 years I have had it. I will do a tune up over the winter or next spring but again this is a piece of equipment I use only once or twice per month.
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Do you have room to put a big heavy pulley on the crank? A nice big iron pulley would probably do the trick if you have room.
Well now I am really confused. It seems to be the general conception that a vertical shaft engine needs a heavy flywheel to be able to run and start without a blade. So after a talk with a B & S tech at B & S he informed me its a myth and carry over from years past. He siad other than the crankshafts orientation the vertical shaft mower is no different than a horizontal in regards to it needing something heavier on a flywheel to make it start or run properly. He stated that a blade does add more mass and therefore more energy, but if its driving something that does not have a large rotating force that may be hard to get started such as a pressure washer pump or such no extra weight is needed, and the only purpose a heavy flywheel is made for is on compliance motors for a brake. He said any of B & S engnes should work fine if they have sufficient HP for the job.

I do remember as a kid fooling with old vertical shaft motors that they would not run right without a blade, but I also recall I have fooled with a ot of them since, all runing in the shop setting on top of an upside down plastic milk crate to hold them in place while running them, and all without a blade.

( I may have the heavy flywheel thing reversed, and that applications without the need for a brake use heavy etc, but the poiint he made is a heavy flywheel is not an indicator of the need to have on an engine without a blade)

I found a new 6.5hp B&S Intek OHV vertical shaft enigne that has a short crankshaft (long enough for my needs though) w/2 year warranty, for $80.00, so it was not a hard decsion to make on ordering it. The crank is only 1 3/16" (not 1 13/16") and is straight 7/8" in diam and has a 3/16" keyway. They were made fro driving pressure washers. I only need 1" of shaft so it will be perfect.

I have since made a "custom" set of pull back type handle bars and got rid of the old tiller handle bars which were about 3" too low, and added a tension spring for the idler pulley and got rid of the manual tensioner. In the pprocess of cleaning up the string trimmer, and hopefully I should have my new motor by mid part of next week.

Evidently I have internal problems somewhere in the motor that was on the trimmer. As I mounted a blade on it and installed it on an old mower frame and its still a real Bi%#% to get cranked, but when running it seems fine......I had previously swapped the alum flywheel to a cast iron one that I had laying around, and it did not make any difference. Then after talking to the B & S tech I finally seen I was in left field with what I was thinking.
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