Weed eater engine conversion

Honda Clutch Housing

Hi Chuck,

I am traveling some this week and will send you some pictures when I return.

WOW! That tubing is expensive. I purchased a 20 foot lenght of 1" OD .125 wall thickness 2024-T3 aluminum tubing from American Metals in Tampa, Florida for $25.00.

I also purchased a 12 foot lenth of 3/8 OD 304L Stainless Shafting from Tampa Bay Steel for about $14.00.

Can't wait to get started on this project.

John

 

Clarification - cheap clutch meant as on cheap motors. If you look at the clutch assembly on say the Bolens 31cc motor, and compare it to the one on the honda GX35, you will see a big difference.

On the question of aluminum tubing - don't be afraid to check out the local Home Depot, Menards and Lowes. They all ahve aluminum tubing but it may be a different diameter. They can always order in what you need as well

Mark

 

Hi John,

I need to order my aluminum tube and stainless shaft material from your supplier! You got enough material to build at least two shafts! That's what I need to do.

Looking forward to those pics. Be safe traveling... people are nuts on the road these days!

Chuck

 

Mark O,

Thanks for the clarification. Like you said, if I saw the two clutches side by side I'd probably be able to instantly tell which one was the "cheap" one. Right now, my plans are to buy the Honda GX35 engine, so I guess I'll get the good clutch. Interesting thought... as the engine accelerates, and the weight (centrifugal force) of the clutch shoes overcome the spring holding them retracted, is the engine turning in the direction opposite the end of the shoes, or in the direction from the shoe pivot point toward the end of the shoe? Inquiring minds want to know!

On the aluminum tubing...John got some in the Tampa very reasonably priced. I did not order the high priced stuff...Mr Frugal here!

Thanks for the info.

Chuck

 

Honda GX35 Power-head

Is anyone on the forum running the Honda GX35 engine? If so, could you give us a performance report, building report and tips. and possibly even a video of that little rascal in action on your boat? Any and all information on this conversion is greatly appreciated. Info like what prop you're using, and whether you're using the clutch or locked it out, and whether you're running a gear reduction would be "icing on the cake". Thanks a bunch. Would like to have all of the kinks worked out on this project "before" duck season. Plan to do that using it in a fishing application this summer. Thanks again.

Chuck

 

Honda GX35

Hi Chuck,

I should be home some time tomorrow. My Honda GX35 motor, clutch bell housing, associated bushings and seals for driveshaft all arrived this week. I will take a few pictures when I get home to show you what I intend to use on my build. With any luck I should have it together next week. No gear reduction on this original build and I intend to use a Young's T-10 Prop.

John

 

Pictures

Hi,

Here are some pictures of the items I received while I was away.

I included a picture of the Honda clutch and also a picture of what I think??? was a Ryobi 31CC clutch. The Honda clutch is larger and the shoes are wider and have lining material on them.

The O.D. of the Aluminum Drive Shaft Housing was about 1.007 diameter and the hole in the GX35 Clutch Housing was about 1.003 so I had to take a little off the O.D. to get it to fit.

The I.D.'s of both the bronze bushings and seals were both good and fit nicely to the 204L stainless shafting. The I.D. of the aluminum tubing was about .764. This made for a loose fit of both the seal and bronze bushing. I can easily drill and tap a few holes where the bronze bushing are located and let a setscrew hold the bronze bushing in place. Not sure what I will do with the seals to give them a good water tight fit.

I will need to size (Square) the clutch end of the drive shaft to adapt to the Honda Clutch Bell output end.

John

 

Helicopter John's Pics

Hi John,

Thanks for posting the pics. They look great. You really have a good looking setup there. I'm dying to see it in action... on the water! Probably nothing like you though! I didn't see your prop? Have you not received it yet? How do you intend to secure it to the drive shaft... threads... roll pins.... squared shoulders?

I'll probably get my Honda GX35 around the middle of next week. I'm having the guy check out what all those letters and number after "GX-35" means. Also, he was going to check to see how long the control wires and cables are... if any.

How is that "bell Housing secured? Is the bearing races secured to the outside housing, and the bell housing secured to the bearing? I imagine it has to be pretty secure to avoid any undue wobbling and wear.

Are you going to weld a bottom skeg on your shaft to protect the prop? I'd feel like I was steppin' in high cotton, if I were just as far along as you are. As a whim, and from someone's suggestion on here, I checked both Lowe's and Home Depot for the outer shaft aluminum and the drive shaft stainless steel tonight...no luck! The longest they have is 3', and the specific alloy is unknown.

One final question... did all of the required parts for the bell housing, bearings, and outer housing come in that one kit you were talking about?

Thanks again. Waiting to see that video! I forget... what kind of boat?

Chuck

 

Youngs' T-10 Prop

Hi Chuck,

I modified my original pictures post and added a picture of the T-10 prop and the associated roll pin that holds it to the shaft. The 304L stainless steel shaft will need to be cross drilled for the roll pin. This is my first build utilizing this prop and can't be sure how it will propel my boat. I will let you know how it works.

GX35 Engine. I purchased the GX35NTS3 (This is the standard pump type) not the tiller type. I will add a close up picture to the original post that shows the S3** designation on the engine I received.

The bell housing doesn't include the 4 mounting bolts and associated lock and flat washers that mount it to the GX35 engine. You will have to pick these up at a local hardware store. I didn't disassemble the bell housing but it appears to have 2 ball bearings that support the clutch bell and associated shaft. I can't detect any wobble in the clutch bell. I haven't checked yet but I am told that the output shaft has a 1/4" square drive. You will have to machine the end of the 3/8" driveshaft to adapt.

The bell housing kit included all the items needed except the 4 bolts that mount it to the engine. Just properly size the O.D. of the aluminum driveshaft housing to fit into the Honda bell housing. The housing has a slit in the side and a bolt to squeeze the bell housing slightly to hold the housing to the aluminum driveshaft housing.

I will add a skeg to the bottom of the driveshaft housing to give protection to the prop.

I have a 12 foot Aluminum Jon Boat.

Now, I have to figure out how I will adapt the seals and bronze bushings to the aluminum driveshaft housing as the aluminum tubing I purchased has a slightly over-sized I.D. (.764). The bronze bushings and seals measure (.752)

Next week should be interesting and FUN!

John

 

Hi John,

Thanks for the pic of your prop, and the packaging labels on all items. This helps the rest of us know what to order.

GX35NTS3 "pump type" engine... how is it different from the "tiller type" engine? Is there a different power range... different carburetor, or maybe something as simple as the timing setting? Should I "make sure" I get the pump type engine?

So, the "Bell Housing" and Outside Housing all came together, as an assembly, right? Bolts and washers are no problem.

John, as to the problem of your outer shaft having a slightly larger I.D. than the O.D. of your bronze bushings. Here's three possibilities... the first is to drill and tap the outer shaft, and install a set screw. Another possibility would be to use split mandrels, that fit tightly around the outside of the shaft, and swage the outer shaft slightly down on the bronze bushings, after they are in the correct positions. The third method would involve drilling a roll pin hole that would slightly hit the bronze bushing outer edge, and sealing both of the ends of the roll pin. This would be a difficult task... getting the drill started at that angle to a rounded outer shaft surface. But, a very small roll pin could hold the bronze bushing in both up and down movement as well as stopping any rotational spin tendency. These tiny roll pin holes could be sealed with a good rubberized sealant, that could be removed, to enable the roll pins to be removed if need be.

Just some ideas... maybe one will fit your need.

Chuck

 

Grease zerts

Hey John -

Another option instead of just set screws would be to drilll all the way through the tubing and through the bushing. You could then tap in a grease zert. This way, the bushings could be lubricated if you ever had a desire to do so. I did this on the first engine but not on anything since.

AS far as the seal, you have a few options. One is to flare out the rim of the seal. Not recommended as it is difficult to do. Could do this on a lathe.

You could also use a little JB weld on the outer edge of the seal and push it into place.

The third option is to find a washer the same diamter as the aluminum tubing and a hole in the middle the same diameter as your shaft. Take some 3M 5200 or other strong adhesive sealant and glue the seal to the washer. Use your shaft to keep the holes lined up when doing so. Let ie cure. After it has cured. use some JB weld or adhesive and glue the whole assembly into the shaft.

Mark

 

Bronze Bushing and Oil Seal Mounting Options & Honda GX35 Engine Info

Hi Guys,

First thanks for you valued input. I have also thought about this today.

I think I will drill the bushing as suggested and install a threaded grease Zerk fitting in the bronze bushings. I will also use a chamfer bit and put a slight taper on both ends of the bronze bushings for ease of re-installing the drive shaft should it ever be necessary.

Maintaining the seal in the correct position once the bronze bushings are installed was my main concern as the seal has a tiny lip and is pretty fragile. I like the suggestion of placing some JB Weld on the outer surface of the seal and installing it and let it cure.

Chuck,

On the matter of choosing the correct engine my Honda distributor here in Florida sent me the attached diagram. It shows both gas tank options. The S3 has the gas tank filling hole towards the top of the engine cylinder and the tiller version has the tank filling hole in line with the crankshaft as that engine was designed to be utilized on a tiller with the crankshaft in a vertical position. The S3 version will work well for me as that will allow me to easily refuel the engine when mounted on the boat. Note: I just added a picture of page 5 of my Honda GX35 manual which shows the standard pump and tiller type configurations.

Other adventures.

I sized the square end of the drive shaft this morning. As it turns out the size of the female output square end on the Honda Clutch Housing was (.201). I had an old weed eater flexible drive shaft that I was able to use to verify the fit and then measured it with my micrometer. I squared the end of the 304L stainless to a length of about 1.25 inches. The actual female hole depth in the Honda Clutch Housing square output end was about 1.0 inch but I wanted to give it a little extra.

Looks like tomorrow I will try to install the bronze bushings, oil seals and upper drive shaft locking collar. I have some locking collars that will work but they are a tight fit inside the aluminum tube. I will remove some material from the O.D. of the collar so it doesn't drag on the inner wall of the drive shaft tubing. If all goes well I will also install a delrin bushing at the bottom of the drive shaft tube and fit the Young's T-10 Prop and cross drill for the roll pin installation.

The next items on the agenda will be to fabricate the drive shaft tilting mechanism and associated throttle handle with cable and kill switch wiring. I still need to find a piece of aluminum plate for the skeg and have my friend weld it to the drive shaft housing. The other option would be to install a cover plate above the prop as others have done in their builds. Not sure how I will attach that at this point.

Not sure on the thickness of the skeg plate. Maybe 3/16 i.e. .1875 thick????

I will post some pictures of tomorrows progress.

John

 

Couple of points

When drilling for a grease zerk instead of a set screw, you will have to clean out the drive tube real well to get rid of the metal filings. I was unable to remove the bushing after drilling the hole (it was a tight fit already and I didn't think I would be able to re-align the holes I just drilled had I removed the bushing) and cleaning out all those filings was a pain.

Also, think through the order in which you do things. Depending upon your welder, it may be easier to weld the skeg on prior to assembly of the drive tube. That welding gets pretty hot (duh) and could do things you don't want to happen should you weld after assembly. On the other hand, welding on the skeg after everything is put together does make it easier to make it straight and all.

Mark

 

Drive Shaft Tube Assembly

Hi Mark,

Thanks for the tips.

Do you remember the thickness of your skeg? I need to round up a piece of aluminum.

John

 

John and Mark Wo... thanks for the plans. Wow! A picture "is" truly worth a thousand words!

John, hope the skeg situation falls in place for you soon. Many years ago, I used to teach most areas of welding... including welding aluminum and stainless steel. I tend to think along the lines of Mark Wo, as to possible distortion and component damage, if welded after assembling the driveshaft. Just thinking out loud. I do believe welding is the way to go, though. Anything around the shaft, such as a clamp, offers the possibility of grass and weeds hanging and possibly entangling the prop. Just a thought or two.