MY apologies if this sounds like a stupid question. It wouldnt happen to be a gear reduction engine? a lot of golf course equipment has gx120 2:1 or 6:1 gear reduction engines. the crankcase is a bit different with gear reduction box slightly to one side. turn it over once and see if the crank turns a full revolution etc.

 

Hello, nope not a gear reduction engine. Just a straight 3/4" shaft coming out of the block. No such thing as a stupid question.....thanks!

 

Hello, I have a good running Honda GX120 to replace my 5HP Briggs on a TracVac lawn vacuum.

The GX120 is rated at 3.5 HP,it is really under powered for that, you should be using a GX 200, rated at 5.5 HP.

You didn't post any numbers off the front of the block, but you can find your owner manual here

You might beable to find your answers in there....

 

Thanks for the info. I had actually gotten the numbers off the block, didn't think to post them, LOL. I realize the engine is lower in HP then maybe I should use, however I got 2 of them for $25 each in like new condition from an auction and when the Briggs took a crap in the middle of the leaf season, I punted. It actually works really well, just needs more RPM. I actually do plan on getting a larger Honda for it as soon as I come across one. Thanks again!!

 

Is it firing on every revolution even though it is a 4 cycle?

Yep. Most all small engines use a magnet in the flywheel which passes by a coil/module/magneto on every revolution, creating a spark. One on compression and a wasted spark on exhaust.
You should be able to get around 3600 rpm outta that little honda, which, again, is what a lotta small engines are rated at.

 

I was thinking that.....so then in reality, I just take the number I am seeing on the meter and divide by 2. So if I set it to about 6000-6200 RPM according to the meter, I should be right where I want to be, correct?

 

Thanks people for the quick replies. I'm new to actually working on small engines, but the principle is pretty much the same as the big ones. I rebuilt my first small engine last winter (Kohler K301) for my tractor and it ROCKS!!! I'm actually very impressed with the Kohlers. I saved the Briggs that came off this TracVac (1980's 5HP) and I plan on rebuilding it knowing it is going to cost me more than buying a new one.....I want to learn and the way to do it is to do it! I'm actually thinking of making one of those toilet go carts with it, LOL.

 

A typical 21" walk behind mower is governed to about 3100 RPM.
It takes a lot of power to move air. Listen to your vacuum cleaner rev up when you block the air flow. No air to move....