Lawnmower Engine Retrofit?

[ZnsaneRyder]

I'm going to use a 3.5HP B&S Horizontal-Shaft edger engine on a bike trailer, but I'm not sure where to post about bike trailers here.

I know it won't be legal, but I don't care. I'm going to conceal the engine, and remove any "Briggs & Stratton" and 3.5HP labels on it, and quiet it down with a muffler. I chose this because lawnmowers are easy to get running, and this is similar to those type of engines. I'll make the trailer look like it's for hauling stuff for my bicycle

Thanks for the info that they are 148cc, I was wondering how big these engines are, since it doesn't show the cc's anywhere on the engine, and that's a good thing.

 

[arceeguy]

Yup - most common lawn mower engines and horizontal shaft utility engines are going to be over the displacement limit for a motored bike/moped. My guess is that if you keep your speed below 25-30mph, you won't get hassled by the cops. If you whiz by doing 45, you will definitely get questioned by law enforcement.

 

[ZnsaneRyder]

Good point. I only want top speed of 30-35 for highways since I live far from the city. I'm mainly wanting power to maintain speed, since I can pedal up to 25-30mph in bursts, I just want the gas to push me along at 15-20 average in town, and save me much energy from pedaling.

I'll keep an eye on the PO, and I'll have a kill switch if I have to shut the engine off.

 

[ZnsaneRyder]

Another thing about the mower engines.....

A while back, I took apart an old junk 3.75HP B&S mower engine that had a bent crank. The engine block had bolt holes in the side which looked like it could be turned to mount horizontally. If this is possible, I imagine you have to align the carb to match.

I wonder if the vertical and horizontal engines are really the same, just with different fuel tank, air cleaner, and carb position....

 

[stude13]

the crankcase is 90 degrees out. isnt it?

 

[muddawg]

running a vert shaft sideways is a neat idea but a 4 cycle engine has an oil pan and the crank must bathe in the oil and some have oil pumps
that need the oil in the bottom to work

the engine must stay in designed position to circulate the oil

a vert shaft may run in the horz position but not for long

mike

p.s.
the trailer deal is a loophole in the laws of some states
and a dam cool ideer...LOL !

 

[ZnsaneRyder]

There's a few people on YouTube already doing trailers, with big engines mostly 3.5hp, and I like the idea of not having to modify the bike much.

Check this out:
http://www.youtube.com/watch?v=XjEgsKqfi74

AND

http://www.youtube.com/watch?v=xp5xRazHd7g

AND

http://www.youtube.com/watch?v=5L8QEYN5w9U

 

[arceeguy]

running a vert shaft sideways is a neat idea but a 4 cycle engine has an oil pan and the crank must bathe in the oil and some have oil pumps
that need the oil in the bottom to work

the engine must stay in designed position to circulate the oil

a vert shaft may run in the horz position but not for long

mike

Exactly!

Small horizontal shaft engines have a little dipper on the ends of their connecting rods to splash oil around and lubricate the engine. A vertical engine uses a gear driven oil slinger to lubricate the engine parts, and the slinger would not work in the horizontal position. Some tecumsehs have an oil pump to lubricate the top bearing too. The carb postion is only the start of the problems!

Passed by another mower in the trash on the way to work........

 

[silent]

Converting vertical to horizontal shaft

A few years ago, I actually converted a Briggs and Stratton 3.5HP mower engine to horizontal shaft. I wondered if it could be done and it can. There are still problems to work out if you're concerned about icing as I used a rubber boot to extend the intake tube. I tried to find a boiler roller so I could expand another tube and press fit it over the existing briggs metal intake as found on the older vertical shafts. They are all plastic now. You also have to install a horizontal shaft-style oil slinger and measure the correct oil level so you don't over fill. I simply drilled a weep hole and put in a screw so I poured in some oil and let it weep out and I knew I was at the right mark. I measured from a reference point in a horizontal shaft engine and made sure my oil slinger stuck down in the oil the correct amount. I left the vertical slinger in the engine figuring it didn't hurt anything. I test ran the engine on the bench for 25 hours in the middle of January are various throttle settings with a hunk of pallet wood on it. The nice part would be you could weld a plate in the bike frame and bolt the engine on to it and have a nice compact mount with a nicely located PTO shaft. The engine would still sit like a wart on the side of the bike but oh well - great use for an old Briggs. Pictures are here:

http://incolor.inebraska.com/elassley_bie//verthoriz/

I have no further info available but you're welcome to write to me at silent@beatricene.com

Enjoy.

Erin

 

[arceeguy]

Wow - nice work! Just goes to show you that where there is will, there is a way!