Lawnboy 5HP

[JKautoFab]

NOS

ive known all of that, yes i know its easier and simpler to use the right kind of engine for a bunch of reasons but thats not the point. you arent seeing my point. do you think honda built a 125 mph lawn mower to mass produce to cut grass at 125 mph? no. do you think it was fun to build, and things were learned attempting it? you betcha! do you think a lawnboy powered mini bike might be just as cool as the dual lawnboy powered go kart? i think it could be, so why all the negativity?:shrug: would i recommend this for anyone? no, would i recommend someone ask a shop to build this for them? not in a million years... but some of us have shops and skills and build crazy things like tanks from car tire tread and mower wheels... do we pshaw them for it? nay i say! :hammer:

 

[Havasu Dave]

but some of us have shops and skills and build crazy things like tanks from car tire tread and mower wheels... do we pshaw them for it? nay i say! :hammer:

Hold on a minute. The OP asked if anyone knew anything about the motor. He got his answer from someone knowledgable on the subject:

"Bad idea all around and should not be done.
Money wasted could build a much better engine from something else. "

Was he wrong? The OP asked the question and got the answer.

What's next, participation awards for the loosing soccer teams? Chinese OHV engines on vintage mini bike frames?????? :hammer:

LMAO!!

 

[JKautoFab]

there are WORSE engines to try to use.... he did make it sound like it was as bad as trying to use a hit and miss or a fleet of tiny gas RC engines :laugh:

 

[Havasu Dave]

there are WORSE engines to try to use.... he did make it sound like it was as bad as trying to use a hit and miss or a fleet of tiny gas RC engines :laugh:

:laugh: Some of those RC Engines are bad-ass though! Not exactly tiny, for just under $3000 you could haul ass I bet. :thumbsup:

 

[Lawndart]

That DA 200 is not mini bike material. It will fly a 40lb airplane but not a mini bike.

I think me got off subject.

 

[Havasu Dave]

That DA 200 is not mini bike material. It will fly a 40lb airplane but not a mini bike.

I think me got off subject.

I was making a point- ANY engine can be adapted and modified to work in any application. Steam, gas turbine, etc.

Pressed together cranks were used on Honda Elsinore motors, so that's not an issue.

Most, if not all lawn mower-purpose engines use the blade as a flywheel, so don't have much of a flywheel for other purposes. (back to airplane engines)

The carb on it, (can't see in photos) might be a CV- I didn't see a float bowl- so no big deal there on mounting if it is.

Engine rotation is a big deal. If it's not CCW, you have to run it backwards in the frame, but that's the easy part of the equation.

Some good and some bad, but possible to adapt, but definitely not the best choice. If it's worth so much to lawn mower collectors, it might be advantageous to sell it to one of them for big dollars, and get a more suitable motor for your purposes.

I love being told I can't do something. Makes it more fun to do it, and like Steve Jobs said, the world is created by people no smarter than you.

As an aside, the first go karts were powered by West Bend two-stroke engines that started out as lawn mower engines.

 

[Lawndart]

OK, The Lawn-boy will idol with out the blade. The carb is trash, not jetted to go over gov. speed. I got the pulley off. Has anyone ever seen a 30 ton press jump 2 inches off the floor, I have. That pulley give the 30 ton press a good fight. Since I had to remove the crank to get the pulley off. I also removed the governor and plugged the hole.
As I was crawling under a table to find a 3/8 socket I realized that the engine was made in America, I going with OMC. The engine went back together grate and still has mad compression.

Does anyone have suggestions on a carb and pipe? (140cc)

 

[Newoldstock]

Does anyone have suggestions on a carb and pipe? (140cc)

HL 166B for a carb.

If it is indeed an OMC product ( I find that hard to believe to be honest ) it may have needle and roller bearings in it, I hope you were very careful not to loose any or brinell the bearings while stripping and assembling it.

I would use a the dremel tool and raise the exahust ports about .100.
Not much else you can do with it to be honest.

This might be an option
Build a "Tuned" pipe for a 2-stroke : Resources
Hydroforming PART 1 - Make Exhaust 2-Stroke ( PROTO RS 500 KTM ) - YouTube

 

[Lawndart]

NOS,
I don't know much about Tillotson carbs. The HL 166B, can I buy new? Is it something I can use on something else?
From all that I have read, no one knows who makes this engine! This engine was only made for two years, if you know who manufactured this engine please let all the people on the Lawn-boy forums know, because it is top secret. They have narrowed it down between two manufacturers, Suzuki and OMC. The Suzuki had a removable jug, the OMC had a removable head. I am assuming manufacturer is OMC because the removable head and standard bolts. If we can pinpoint a manufacture, we will be god's to a lot of Lawn-boy geeks. The intake and exhaust ports are D shaped, does that help with manufacturer?
Yes, I did brinell the crankshaft! And it passed with flying colors. I was very careful with connecting rod and crank bearings. I did remove the crank bearings from the crank shaft, the flywheel side fell off but the PTO side needed a light filing of the shaft to get off. All parts were washed and inspected before reassembly.
Exhaust port, If you mean internal exhaust port. That is something I'm not wanting to mess with at this moment, but I would ream the wrist pin. If it's is really a ported piston. the hole is not very big.
The video on hydro forming tuned pips was awesome. I fix a lot of pips by capping off and freezing them. But tuned pips are all about harmonics. I don't think I could design one that would help performance, honestly. I was hoping for suggestions of something I could get out of a gunk yard possibly.
NOS, I appreciate all your input and knowledge.

 

[delray]

maybe just little more info......:shrug:

Very rare Lawnboy C21ZPRB push lawnmower. This machine is a true commercial model with steel ball bearing wheels with grease fittings. This unique Lawn-Boy model features Lawn-Boy's powerful M Series 5 HP 2 stroke piston ported engine supplied by Suzuki. It also is one of the last Lawn-Boys to feature a light weight magnesium deck. Requires a 50:1 gas/oil mix. The entire mower has been thoroughly cleaned and degreased. The Mikuni carburetor has been disassembled, cleaned, and reassembled. It looks good and runs strong and has the unique M Series sound. Includes original rear grass bagger.


Lawn Boy C21ZPRB Commercial Push Lawn Mower for Sale in Bay Mills, Wisconsin Classified | AmericanListed.com

 

[delray]

little lost with C21PRB that should be a M ?

i believe here is a diagram of the engine broke down
Parts and Diagrams for Lawn Boy C21ZPRB, Lawnmower, 1991 (SN K00000001-K99999999)

 

[Newoldstock]

maybe just little more info......:shrug:

Very rare Lawnboy C21ZPRB push lawnmower. This machine is a true commercial model with steel ball bearing wheels with grease fittings. This unique Lawn-Boy model features Lawn-Boy's powerful M Series 5 HP 2 stroke piston ported engine supplied by Suzuki. It also is one of the last Lawn-Boys to feature a light weight magnesium deck. Requires a 50:1 gas/oil mix. The entire mower has been thoroughly cleaned and degreased. The Mikuni carburetor has been disassembled, cleaned, and reassembled. It looks good and runs strong and has the unique M Series sound. Includes original rear grass bagger.


Lawn Boy C21ZPRB Commercial Push Lawn Mower for Sale in Bay Mills, Wisconsin Classified | AmericanListed.com

Just from the looks of it I would have to say that enngine would make a hell of a good lawn mower....

Somethings are kind of a give away its not an OMC product.

The jap carb abd piston porting.
Both things OMC did not do.
They made their own carbs or used a walbro ( and when they switched to the walbro it was the end becuase their own carbs had become real crap )

HL 166b is a very common carb used on a lot of small two strock aplications same size as this engine.
It may even bolt on.

The important think is its a diaghram carb so it willl run in any orientation andit 5/8 venturi so that is a big carb for something like this.

I looked at the parts break down.
Weak link apears to be the rod with no needle bearings.

Piston porting will reduce its top end.
maybe you better leave the port alone adding a little hight to the exhaust will not help here with a piston port because you pull much extra fuel on the top end from this.

 

[Feedoggie]

Lawn-Boy made so many different models in their day. Too bad things went bad for them and Toro got to them. The above mower is certainly a NEAT Piece. Long-live the TRUE Lawn-Boy 2-stroke staggered wheel design. If you're lucky enough to get hold a good one, grab it.

 

[Newoldstock]

Lawn-Boy made so many different models in their day. Too bad things went bad for them and Toro got to them. The above mower is certainly a NEAT Piece. Long-live the TRUE Lawn-Boy 2-stroke staggered wheel design. If you're lucky enough to get hold a good one, grab it.

????

They made 4 engines, maybe 5 or 6 decks.
Everything else was a variation on a previous design.
Furthermore most parts could be back sourced to an outboard.
Need a carb float for your 1958 lawnboy?
Try a JW-10 carb from an outbard....

 

[FirePowerMinis]

I see 1-2 per week at the local recycling yard. I grabbed one with spark and compression for $.16/lb

 

[Lawndart]

It is definitely not a Suzuki. It has standard bolts.

NOS, Thanks for the carb suggestion. The crank and rod come as an assembly, It should have needle bearings of something. I think it will be ok.

 

[charlie73]

I have 20 plus years tillotson experience from working on vintage ski-doos. Let me know what I can help you with. I doubt you will be able to replace that tilly with a brand new one of the same. Tillotson made more tooling changes than fomoco in the era. If u have a mostly complete carb I can walk u through rebuilding it.

 

[Lawndart]

I have 20 plus years tillotson experience from working on vintage ski-doos. Let me know what I can help you with. I doubt you will be able to replace that tilly with a brand new one of the same. Tillotson made more tooling changes than fomoco in the era. If u have a mostly complete carb I can walk u through rebuilding it.

It has a Mikuni on it stock. I need a good Tillotson.

 

[Newoldstock]

It has a Mikuni on it stock. I need a good Tillotson.

FInd a Chainsaw shop.
Any place that fixes saws will have at least 1 sittingina box.

Check the throttke shaft and bushings are not worn out.
if its in a box of parts the reason may be because its worn out...


Something...
Anything around the right size off a saw will work.
Tillotson HL27B Carburetor Homelite Chainsaw Westbend Etc | eBay

They are out there.....

http://www.ebay.com/itm/STIHL-VINTA...918?pt=LH_DefaultDomain_0&hash=item3cdc85fb5e

 

[Lawndart]

Thanks! NOS.
I have been trying to find the time to go talk to my flying club Buddy at the home and garden, he is the 2 stroke man. Work has been kicking my but lately. I some how managed to get off Monday for Memorial day, I hope to run in to him at the flying field. He might have something in a box.