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Discussion Starter · #1 · (Edited)
I took up jackmels' offer of a free Toro 521 that was missing the engine, pulley, belts, and the chute crank worm gear:



As I recently did a Predator 212cc swap on a 1974 Toro 524, I had a spare 5hp Tecumseh H50 with a suitable pulley. I only needed to swap out the extra long oil drain tube(so that it would clear the tall tires) for a shorter one, and I also had to mount a throttle lever on the handlebar.

Picture of donor:



Here's mid-progress pic:



I also installed a spare electric starter while I was at it.

Items that are en route: belts/chute crank worm gear, and skid shoes. I should have it running next weekend.
 

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Discussion Starter · #3 · (Edited)
New belts, chute crank worm gear, and the skid shoes are on. It runs and drives!

The previous owner of the donor Toro 524 said that the engine would struggle to move heavy snow. I think I know the reason why; while I haven't verified with my sirometer yet, the max rpm seem to be well short of 3600.

If anyone else needs to tweak the high speed RPM on a 1970s medium frame Horizontal Snow King engine, I'm attaching a pic from the 123-page Tecumseh Technician's Handbook.
 

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I too have a repowered Toro 521 that I installed a Harbor Freight Greyhound 6.5 back about ten years ago.It has worked well with few problems.


Lately,I've noticed that people eagerly recommend the replacement of any Tecumseh 5hp engine with a Predator because of a supposed huge increase in power.


I,myself,have never noticed an increase in power after installing the 6.5hp Greyhound in place of the Tec.HS50.I have noticed that the GH is quieter,more fuel efficient and starts very easily at any temperature,but more powerful-not really.


I recently came across some spec. sheets put out by Tecumseh for various engine models dating from 1974 up though the early 2000's.The horsepower and torque ratings are given for each model.


I noticed something I found interesting.The Tecumseh H,HS50 engines are rated to produce 8 ft.lbs. torque at 2800 RPMs.The Predator 212 is rated for maximum torque of 8.1 ft.lbs. @2500 RPMs.


Honda recently de-rated the GX200 from its former HP output rating of 6.5 down to 5.5 HP.They stated this was a more accurate figure based on new test standards.


I wonder how accurate the 6.5 HP rating for the Predator actually is?I've seen dyno results for highly modified Predators but never any for stock engines.It would be nice to see how close they come to published specs.


EDIT:I just noticed on Harbor Freight's website that the engine specs listed for the 212 are considerably different in the "Predator Beats Honda" comparison chart.There,they have the horsepower listed as 6.1 and the torque output boosted to 9.7 ft.lbs.I raise an eyebrow in suspicion over this.
 

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Discussion Starter · #7 · (Edited)
Here's the buttoned up picture. I ended up installing a prettier throttle lever (one that actually has stop/slow/fast labels), plugged in a spare harness for the on/off key, and threw on a new Toro friction disc.

The H50 runs well and it should be a good match for the frame.



The only other thing I might change is to use a 90-degree elbow for the oil drain tube and go back to using the original longer tube so that it runs to the back of the blower.
 

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Discussion Starter · #9 · (Edited)
Here's a long overdue update... I've listed it for sale for several week but had zero interest, not even a single "Is this available?" nonsense.

I decided to change it up a bit and installed a Briggs Intek 12000 series engine on it. It's an OHV design, 6.5 HP, 206cc, and supposedly made in the USA in the late 90s... It's a better match for this 521 as I think it's also from the 90s.

I'm using the typical 3/4" to 1" crankshaft adapter so that I could reuse the Toro pulley and the existing belts. Everything bolted on. The only issue was the chute crank not clearing the valve cover which most folks here know that it's a common issue with a 521 engine swap.

171607


I purchased a $3 coupler nut from a local hardware store to get the needed clearance.

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It runs and drives fine and we're supposed to get up to a foot of snow. I'll give it a whirl.
 

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Discussion Starter · #10 · (Edited)
I got to test it out in the foot of snow earlier this week and it worked well as I knew a repowered 521 would.

However, it turns out that the Intek's gas tank has a leak at the fuel line fitting, and that tank is somewhat expensive to replace. I also didn't like how the eye bolt for the chute crank had to be extended so far out. The new extra width made the entire snowblower awkward to use between cars.

I yanked out the Intek this evening and replaced it with a recently revived Hemi Predator (it came to me with a stuck intake valve).

The Hemi's valve cover sticks out far less than the Intek's, so I don't even need the coupler nut anymore to have the chute crank rod clear.

Here's a mid-progress pic after the Hemi was installed.

172048


I may even wire up the original on/off switch to the Predator's kill switch at some point.
 

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Discussion Starter · #11 · (Edited)
The on/off key at the control panel has been wired to the Predator's kill switch setup:

172201


I've installed my DIY adjustable carb jet with the original main jet having been enlarged with a #60 drill bit:

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All that is remaining is a slightly shorter auger belt. The original belt is 29.5" but it slips even with the tensioner rod set to max. A 29" belt is too short to slip over the pulley, so I had to wait for a few days for a 29.3" belt to be delivered from Amazon. I was able to slip it over the pulley and it works as hoped.
 

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Discussion Starter · #13 ·
We were hit with about 8" of fluffy snow today. I got to try it out with the max RPM adjusted up to 3900 rpm. What a nimble and powerful snowblower this guy is! However, I joined the "Predator tank vent club" earlier tonight as it kept stalling. I ended up doing the mod out in the back yard. I'll try again in the morning.
 

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can you show the tank vent mod? thanks
 

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got it , thanks
 

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Here's the buttoned up picture. I ended up installing a prettier throttle lever (one that actually has stop/slow/fast labels), plugged in a spare harness for the on/off key, and threw on a new Toro friction disc.

The H50 runs well and it should be a good match for the frame.



The only other thing I might change is to use a 90-degree elbow for the oil drain tube and go back to using the original longer tube so that it runs to the back of the blower.
[/QUOTE

can you please share what you used for the remote throttle?]
C
 

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Discussion Starter · #19 ·
Hi. I have a 421 that I installed a Predator engine on. I would like to connect the key switch. I see in your picture you have one wire going to ground. Where is the other wire connected?
You want to splice the other wire to the kill wire that goes to the ignition coil. It is used by the black wire coming from the oil-pressure sensor.
 
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