Outdoor Power Equipment and Small Engines - Snowblower engine swap

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View Full Version : Snowblower engine swap


otis451
12-29-08, 01:19 AM
Hi all. Looking for any tips or pointers anyone can offer. I have an old ( 35 years + ) AMF 2 stage snowblower with a Tecumseh H70 engine that I've been using for about 10 years. Never really have had any serious problems with it until this season. One by one, every little thing that could break on it has. All have been pretty easy fixes. It's always smoked a little, so I usually check and add oil every third time it runs, which I did a couple nights ago. So this morning when I started it, it got 10 feet and stopped dead. Checked the oil - bone dry. Pulled the belt housing off and checked the crank - it turns nice and easy, right up until it hits the broken rod in the case. Ok -so now its time to rebuild or replace my engine. It was obviously going through more oil suddenly, so it threw a rod and may have finally lost the compression rings.

So - I find this almost new Tecumseh 10 hp in the back of my garage that I forgot about 3 or 4 years ago that runs a generator that I rarely use. And seeing as a couple more storms are coming this week, I'd like to get my machine up and running soon.

I looked the generator over and took some measurements, but it looks like I should be able to swap the 10 horse onto the blower with only a few sheet metal modifications. I'll need to adapt the shrouds for the recoil and for the carb, and since the generator is load governed I'll have to use the manual primer and throttle links from the blower motor. Still not certain if they have the same length and diameter of output shaft, but would be easy enough to fit a different pulley. My questions are - should I use the same size pulley, or should I change pulley size to compensate for the higher horsepower ? Also, are there any other mods I should make that anyone else can think of to "winterize" the new motor ?

Thanks for any ideas.


trouts2
12-29-08, 03:07 PM
The old engine maybe 3200 and the new 3600. If 3200 the spec was probably plus minus 150 RPM so the 3600 ok. There will be a tourque increase with the 10hp. If the old machine is in good shape and built well it should be ok.
You could run with the 3600RPM or slow it down with the screw on the throttle control (maybe under the plate over the carb) if it has one or just set max RPM at 3600 and when you get into heavy conditions lower the throttle a bit.
The 10 should toss a bit better with the increased torque.

In general companies sell a single body type with a several variations of motors. The parts are interchangable. Your snowblower model may just have sold with an 8, 9 or 10hp and be fine with a 10. I don't know who made your snowblower but possibly you can lookup online and find out if that model sold in higher horsepowers.
David

bontai Joe
12-29-08, 08:36 PM
One relatively minor point, don't forget to remove the air filter on the new engine, otherwise it will ice up and prevent air from getting to your carb.