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Troy Bilt Junior engine replacement

36K views 22 replies 7 participants last post by  vonfatman 
#1 ·
I bought a TB Junior and the crank is busted. What retro engine replacement has anyone done? It has a double pulley on the back of the motor. Can this cover be removed and bolted onto another Tec or Briggs motor? I believe it is a 3 hp? Trying to find the manual online now.



 
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#2 ·
Other than a bad engine, it sure looks to be in good shape. Looks like you did pretty good. I would have to wonder what broke the crankshaft though.
 
#3 ·
I don't know what would have broken it? Maybe low on oil and heat?? It is in really good shape and I hope someone replies on here. I am finding some H35 Tecumseh motors on ebay but they are all single shaft. I wonder if I could take a single shaft and use my cover and aux shaft parts to make one?
 
#4 ·
I'm sorry, but I have no idea what engine would fit. The low oil and heat theory makes sense though for breaking the crank. The only Troy-Bilt that I've ever messed with is my old Horse with a 7 HP Kohler on it. I'm sure someone will have an idea and will chime in soon though.

Is the gear box still tight? The only other thing that I can think of to break that shaft would be getting the tines fouled up, but that should shred the belt before damaging the engine like that.
 
#6 ·
Ronnie, the belt is outside the bracket I guess because the shroud is missing and I was poking around with them. I don't know about the straight up / down like other tillers unless I had some pics to compare to. I found a side where some newer briggs inteks were adapted to the Pony models with a aux shaft but it did not give me enough info if it would work with this Junior model.
 
#11 ·
Right,
All you need is a long block that will accept the parts from your old engine, Tec. engines were built the same for MANY years. Therefore as long as you get an engine that mounts the carb and muffler the same as yours and is close to the same HP, you swap your cam with the shaft and sump onto the new engine. OR where did the crank break? did it damage anything else? I probably have a crank here if you want to swap it in. I am in the midst of 2 weeks of building engines for spring, so I am in the middle of organizing any leftover parts that I have this season.

Dan
 
#12 ·
I don't know where the crank broke but it is locked up and the PO took the carb off and kept it for another motor. I got the "broken shaft" if you call it that

Not worried about it, but now that I know I can buy a H35 and swap some parts I feel better. I can buy the motor in the picture for $150 with FREE shipping. I can use the rear cover and aux shaft parts and swap sides with the gas tank and it should work.

Sounds like a plan to me. I really want to get this tiller going as it will be used between my rows due to the narrow width.

I have a 44" hydraulic tiller that will do the most work in garden prep. As soon as I get a pump bracket made for it, it will be behind my JD400.

I have got way to many irons in the fire now and not enough time
 
#15 ·
Dan, I took the sump off and it was a broken rod that killed it. Look at these pictures and tell me if you can swap the cover on any H35 motor. also , do all H35 motors have the gear on the crank like I am pointing to in one pic? I should be able to remove the new motor cover and replace with my parts. Any secret to holding the lifters in place while putting the cover/camshaft on? I would think to maybe use vasoline to hold them up while putting the cover on? How are the lifters ran on the engines without aux shafts? I would guess just like this one except minus the exterior shaft/pulley? Also , what is the trick to aligning the cam when installing the cover back?

The cam and all gears look fine. Also the crank looks good.

thanks for all your help on this. Sorry so many questions.



 
#16 ·
I can't see very well in the pictures, but if it just broke the rod why are you replacing the engine? Also, before ordering the engine, you need to get the cam out to make sure that the sump is good. Use a porta power to remove the gear from the shaft after taking the set screw out.

Dan
 
#21 ·
The Junior is a little narrower than the Horse was and allows me to get another row or two in. Matter of fact we are close row planting this year for the first time on our beans and see how that goes.

As promised, here are pics of it finished.. Purrs like a 3.5hp kitten. I do plan on changing the muffler and going with a cigar type muffler with a 90 deg elbow out the left side.

Thanks for everyone's help.


 
#22 ·
Very nice! :fing32:

I'd love to find a little Junior for cultivating during the season. I love my Horse, but it is a little big for tilling between rows.
 
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