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Toro 724 - 38050 - Blown Connecting Rod

15K views 62 replies 12 participants last post by  unknown1 
#1 · (Edited)
Today I picked up this 30+ year old Toro

Model: Toro 724 - 38050 Ser 9000953
Engine: Tecumseh H70-130176D Ser 81320
Connecting Rod: Tecumseh 32591C eBay: $18

Photos:https://goo.gl/photos/pUg518MMahSJteiQ9https://photos.google.com/album/AF1QipOmru4EfhOZckmxMPwMYpzDy4n4f6GDjH2vJOy2

As you can see, the case is cracked where the electric starter used to be.
The previous owner salvaged the starter for his other Toro. He was running it last week when it suddenly started blowing smoke and seized.

I have zero hands-on experience with 4 stroke engines but have watched lots of videos lately. My best guess is that the connecting rod shattered.

If that's true, a generic replacement is about $18 shipped on eBay.

Question: can JB Weld be used to fix the crack in the crankcase cover. I am hoping it should be fairly low pressure and reasonable temperature in there and that all it needs to do is seal well enough to keep the oil in place... does that sound about right? I've seen videos of people doing that and posted one below.

Any opinions would be welcome.

Links for reference:
Engine:
https://www.jackssmallengines.com/Jacks-Parts-Lookup/Model-Diagram/tecumseh/26253/88454

Snowblower:
Toro 38050 Parts List and Diagram - (1000001-1999999)(1981) : eReplacementParts.com

Connecting Rod:
Rod Connecting Tecumseh Rotary 6769 Prime Line 7 03864 Sunbelt SB 6769 | eBay

Links to DonyBoy73 repair videos:



JB Weld Crankcase:
https://youtu.be/zb-kXty8bTY?t=324
 
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#5 ·
Thanks for the pragmatic and realistic answer.
I guess you mean these Predators (presumably Honda clone)..

Gas Engines – Save on Replacement Engines at Harbor Freight

Looks like they've gone up $20 to $119
Or were you thinking of a different engine perhaps?
If so.. can you add a link please.

The Snow engines from brandnewengines seem quite a bit more expensive.
Briggs & Stratton Snow Engines


I need to go find and watch videos and do some research. I'm sure there are good repower threads and videos explaining how to do this for a newbie like myself.
Hopefully it's a straight swap with matching bolt holes and shafts etc.
Who knows... maybe 4 bolts and a couple of pulleys and you're done.

Having said that, one day I *DO* want to play with fixing up an engine.. just for the learning experience and the satisfaction of spilling oil all over the place. ;-) Maybe I should do both.
 
#4 · (Edited)
I put a Harbor Freight Predator 212 on a Toro 724 this week. In my opinion the engine swap could not have been simpler. I had to buy four longer bolts for the tractor to engine attachment. On mine, the output shaft was the exact same size and location. Pulley swapped directly over and used existing belts. I did have to buy a new bolt to attach the old pulley to the Predator shaft because it was a different width.
Seriously Eeezee Peezee.

Oh, I also spent some extra time extending the more convenient Toro key switch wires so you didn't have to use the engine mounted kill switch to turn it off.

Modifying the crank handle location due to interference with the Honda clone valve cover however took a bit of creative fabrication.
 
#6 ·
#10 · (Edited)
#11 ·
Today we have a complete sub-forum on "re-powering".
Re-Powering - Snowblower Forum : Snow Blower Forums
You will find many threads where members used this engine.
I dont remember them ever selling for more than $119, but it probably has said "on sale" at this price.

Jackmels posted a code a month ago for $99, but it expired yesterday. I'm not sure if that worked for in-store pickup.
 
#12 ·
If you look in the back of magazines like Popular Science and Handyman - you will find 20% off coupons and special offers. I see one in there for the 212cc right now for $99. You might also take a look on your local craigslist and make sure you can't snag something that has a different problem other than the engine to grab for parts. For instance I got a power washer with a Honda GX engine for less than $50 and it worked out great. Other people say theirs has "carb problems" quite often - that would be a good grab.....
 
#14 ·
Thanks for all the buying recommendations. I'll check out the re-powering thread too.

I just called Harbor Freight online number and told them a tale of woe regarding the expired coupon code. Their call center gave me the engine for $99.99 plus $7.25 tax and $6.99 shipping. (I should have said $99 even but I said $99.99). I thought that was pretty decent of them.

So I've got an engine on its way!

I think I will go ahead and take a peek inside the old Tecumseh and see if it looks OK except for the (anticipated) connecting rod issue. Maybe I'll then try some JB Weld and see if I can Frankenstein the case back to life. Nothing to lose. It's a great low-risk way to learn and to make all my newbie mistakes on a "disposable" engine.

Thanks everyone... I'll keep you posted with my usual overkill on documentation and pictures as I re-power this machine and hack the old engine back together.

Wish me luck!
 
#16 · (Edited)
The sales folks weren't doing me any favours.

Current coupon shows $99.99 - Expires 1/31/2016

This link will change over time as their offers change... but at the time of this post, the $99.99 coupon is halfway down on the right hand side.

Predator for $99.99:
6.5 HP (212cc) OHV Horizontal Shaft Gas Engine EPA/CARB

Coupons:
Harbor Freight Tools – Quality Tools at Discount Prices Since 1977

Coupon number: 39431263
Standard Emissions - Item: 69730
CA Emissions - Item: 69727
Expires: 1/31/2016
 

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#15 ·
More than likely the reason it chucked the rod is due to the fact it lacked oil/lubrication and the rod seized to the crank which is what breaks them most often - or it over-reved and let go. If the crank is toast your fighting a losing battle on cost.....
 
#17 ·
Question: can JB Weld be used to fix the crack in the crankcase cover. I am hoping it should be fairly low pressure and reasonable temperature in there and that all it needs to do is seal well enough to keep the oil in place... does that sound about right? I've seen videos of people doing that and posted one below.
I've done quite a few of them that way. It works well. I can't see your pics but if you have a large hole pop rivet some fine aluminum mesh over the hole first to give the JB weld something to stick to. If it's just cracked carefully tap it down so it's flat or close to flat and clean it up really well with brake clean and then apply the JB Weld.

More than likely the reason it chucked the rod is due to the fact it lacked oil/lubrication and the rod seized to the crank which is what breaks them most often - or it over-reved and let go. If the crank is toast your fighting a losing battle on cost.....
The crank almost never goes bad, but everyone thinks they do. They look destroyed because of the aluminum transfer from the rod, but they can be cleaned up with some emery cloth, I've done quite a few of them.
 
#18 · (Edited)
I've done quite a few of them that way. It works well. I can't see your pics but if you have a large hole pop rivet some fine aluminum mesh over the hole first to give the JB weld something to stick to. If it's just cracked carefully tap it down so it's flat or close to flat and clean it up really well with brake clean and then apply the JB Weld.



The crank almost never goes bad, but everyone thinks they do. They look destroyed because of the aluminum transfer from the rod, but they can be cleaned up with some emery cloth, I've done quite a few of them.
Forgot to share the pictures... they are now shared.
https://goo.gl/photos/pUg518MMahSJteiQ9

On my youtube travels I bumped into a video showing a before and after while removing the aluminium off the crank.
I will try to remember where that was and post it here.... I seem to remember it was while researching acetic acid versus evaporust versus hydrochloric acid.

Here it is:
Hydrochloric (muriatic) acid
(you can rewind to see the whole thing)
The mumbling is because he has his head in a gas mask at this point to avoid fumes.
https://youtu.be/m-gO3bcSneM?t=265


and then sanding:
(rewind here too if you wish)
https://youtu.be/bCyACIpxJng?t=103
 
#19 ·
That crack looks pretty serious to me, I wouldn't hold my breath on your suggested repair proposal.
But, if you have nothing to lose really but experimenting, what the he**.

 
#25 ·
the tecumseh engine in that video sounds likes it ready to chuck the rod even after a rebuild and must have cylinder damage because its burning oil. just listen to it when he shuts it down @ 2:19! shes not gonna last more than a few uses.

https://www.youtube.com/watch?v=ID1f6WA7J_A

I just posted a comment on youtube to find out how the machine lasted.
Over there.. my account is learningbluesdance... don't ask.. :)
 
#27 ·
That crack isn't that severe. I've fixed far worse including ones missing an entire 2" x 2" piece. You have to remember these things make no oil pressure, they're splash lubricated. It's not a repair I'd do for a customer, but I've fixed a good half a dozen engines this way for my own personal use and have had no issues.

I'm not for or against repowering, just saying this is easily repairable for the price of a rod, some gaskets and some JB Weld.
 
#28 · (Edited)
Great to hear! That's what I originally hoped and it's good to have that confirmed.

The only thing getting in the way now is my total lack of experience... but there's a first time for everything and I'll learn a lot. I think that the Hydrochloric acid in the earlier video might be the key to cleaning the journals properly and I'm glad I stumbled into that video.

So far I've got the engine off. That was laughable to see as I tried to figure out how to do it. Took me an hour! If I were to do it again it would take 5 minutes! Just to document the steps for the next newbie who follows in my footsteps...

1) Do not try to stand the machine on its auger. This machine is not like the ones on Donyboy's channel. In fact you can't stand it on its auger... it will end up upside down with all its weight on the gas cap and choke lever. Don't ask how I know that!
2) Remove Carburetor heat box. 2 small screws and 2 bolts. (remove choke knob first and disconnect primer fuel line from carb when box is off)
3) Release throttle cable holding-bracket enough to let the cable slide out (1 screw)
4) unhook throttle cable from carburetor
5) disconnect kill wiring below carburetor. One screw and one bolt. When the wires are free put the screw and bolt back
6) Unscrew the 4 Large bolts holding the engine platform. There are no nuts underneath to worry about. These bolts are tapped into the thick sheet metal. Ignore the 4 smaller bolts on top of the platform.
7) The engine is now almost free. Just need to get the two belts off.
8) tilt the engine and wiggle off the auger belt.
9) The drive belt is a little more tricky.
10) find the pulley that squeezes the drive belt. Loosen but do not remove the two bolts holding that pulley in place. swing the bracket that holds the pulley out of the way to totally free the pulley and take all pressure off the drive belt.
11) Now you can wiggle the drive belt off.
12) Lift the engine off.

Newbie Photos:
https://goo.gl/photos/qbZ9rmrbXQbWJGhC9
 
#35 · (Edited)
Thanks for the pictures of the re-drilled platform.

Boy that's going to be messy when you change the oil.

So far I have noticed two pet hates on these Honda Chondas

1) Flaky red kill switch... guaranteed to break after three twists.... OK I exaggerate... four twists. First thing I did on my re-powered Craftsman when it snapped off was to add a toggle kill. On these Toros you can hook up the key switch and will therefore never need to touch the little red plastic thing.

2) Oil drain is set back too far... they should have added a two inch drain pipe as standard. My old Tecumseh has a really nice long one. Who wants to pay $18 for an after-market flexhose just to change the oil on a $100 engine? I wonder how many people miss oil changes just because of this? Of course, 2 inches is not enough for this Toro... but it would be adequate on my Craftsman.

C'mon.... 15 bucks for a piece of plastic!!??
Form A Funnel | Shapeable Funnel for oil changes and funneling | FORM-A-FUNNEL ® | Funnel for changing oil without the mess

$18 for a piece of plastic hose!!??
http://www.amazon.com/Drainzit-HON1010-Changing-Honda-GX110/dp/B000PDOEGI/ref=sr_1_2?s=lawn-garden&ie=UTF8&qid=1451809386&sr=1-2&keywords=honda+oil+change+hose


I'm thinking that a creative way of slicing a gallon milk jug might work... hmm off I go to make one.
Here's prototype #1
 

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#34 ·
If this thread seems a little confusing.. it's because I am undecided about two competing options..

1) Repair a Tecumseh engine with a probable broken connecting rod and cracks in the engine case
..or..
2) Repower with a Predator 212

There's some really useful newbie information in here for both options...but it's all intermingled. Thanks to everyone who has helped so far! If my how-to pictures and docs seem ridiculously basic... it's because that's the information I would have liked to have had.... it might help the next newbie.

My current strategy is to try to repair the Tecumseh. If that fails or if I screw up, option B will be to do the Predator repower.
 
#36 ·
I had an idea for the oil change problem, but haven't executed it yet. Buy one of those hoses and then when I want to change the oil tip the machine up on the bucket and switch the plug for the hose. Then let it down and drain the oil. Tipping the machine up pushes the oil away from the drain plug so if you have several of those engines it would allow you to use 1 hose on all of them.

As for the switch, my original Predator is holding up fine, but the new one that I barely used was broken off when I pulled it out of the shed. I had to glue it back to the recoil cowl. I did have a bunch of stuff piled on it, so something must have hit it and broke the clip off the back side.
 
#37 ·
Yes those hoses may be the way to go. Here's a video of the folks who sell them. It's kinda funny.. he keeps talking and talking and talking trying to avoid that critical moment when he takes off the oil drain plug. But it comes out well in the end (with cold oil).



My machine won't stand on its auger..does yours? Must be slightly different models. Mine will just roll over and sit with 200lbs of weight sitting on the gas cap and choke!

As for the switch..... told ya so... the Chonda switch gremlin snuck in when you weren't looking. High quality flakiness.... whine whine whine ;-)
 
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