New Engine To Replace 3.5 Briggs?

The engine is vertical shaft. There is a v belt running horizontally under the engine platform which links the engine to the gearbox. The gearbox then has a chain drive to the wheel.
 
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Does this engine have point style ignition? My late 1970s rototiller had similar problems, I installed the Briggs Magnetron ignition and it runs like new. I believe the old coil was failing.
 
Originally Posted by Mr_Joe
I have a new primer bulb, gasket & carb cleaning, & a few other things. At this point I was planning on changing directions.

Yes, the shop may of been suspect. Total carb replacement may be an idea.




Whenever those engines are hard to start, it's either 3 things:

1. The primer bulb is not working
2. The carburetor diaphragm needs to be replaced (2 gasket looking things that cost under $15)
3. The carburetor is dirty

You can buy entire tank/carburetor assemblies on eBay for $40. A replacement carburetor is the route I would take and I bet it would run good as new. It's also possible the bolts have loosened on the intake manifold, and the little pipe that connects the carburetor to the cylinder head isn't sealed. I've seen this happen a few times. Pull the fan shroud (3 or 4 bolts) and it should be obvious if the bolts are loose since it's right on top of the engine.
 
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I'd be checking that compression before I tossed out an engine probably didn't get much use. You're gonna find almost none of those type engines ever really fail themselves. It's the carburetor it's almost always the [censored] carburetor caused by crap gas. You have to consider to just how much use that thing did not get dragging airplanes around occasionally. I'd be almost willing to bet my pension that that thing has less than a couple of hundred hours but did a lot of sitting around with no one changing the fuel Just like a lawn mower. .
See if you can find one on eBay that matches up to that thing and toss it on for a whole $20. It will likely be the best 20 ever spent. Meanwhile clean up those magnetic pick ups on the fly wheel. It might not be a bad idea to yank the fly wheel and make sure the key isnt broken and shifted Some. I just played that game with her two-year-old riding lawnmower and believe me the first sign is not running quite right, weak and getting worse from there until you get overheat going on with backfiring. All the stuff cost you about nothing beyond the 20 bucks.
When you get it going again do yourself a big favor and make sure it gets a steady diet of 100 low lead. At least you can leave that laying around in the carburetor without destroying everything unlike regular gas.
 
We repowered an old Ariens riding mower after 20-25 years... A while back. It was just a matter of understanding the type and configuration of the shaft and mounting. Some ancillaries didnt quite fit perfect (like the gas tank), and we had to make a shim in one spot for the proper support and tie to the frame, but it worked perfectly.

This engine is smaller (we were doing a 8-9HP one) and looks like a lawnmower or pressure washer engine.
 
Briggs Quattro is superior in every way & usually cheap or free when neighbors leave them on the street during scrap pick up in springtime. (usually just loose blade, fouled
spark plug & plugged air filter issues)
The engine you have tends to have the cowling cut into the intake pipe, which is usually plastic instead of the previous design metal pipe, JB Weld & check the tiny bolts
& gasket at the pipe to intake port entrance & see if that doesn't solve the hard start issues. The other place to check is blown head gasket, the bolts near the
exhaust port get loose & blow head gasket near the exhaust valve.
 
Thanks for the tips. I did replace the carb gaskets, then put in a new primer bulb. The power tow is at a reputable shop with great reviews, it will be 10 days or so before they get to it. I talked to the power tow co in Idaho, very helpful. A new unit is about $2k, delivered. They don't sell any engine that would work for this 1980's or early 90's unit.

Yes, likely this engine has very few actual hours on it. Once running, it does it's job just fine, especially with ice or snow on the pavement. I had no appreciable improvement with my carb & primer bulb refurb. I went off utube tutorials.

I put a $100 limit on work before we talk. If the engine itself is ok, one would think a brand new carb could breathe life into the motor. I appreciate the helpful hints.
 
Originally Posted by mk378
A mower depends on inertia of the blade to act as additional flywheel. Make sure to get the "heavy flywheel" engine option for applications like this where there is no blade. Starting is otherwise difficult or impossible.

The bolt pattern on the base of the engine is very standard. There are three standard shaft diameters: 7/8 inch, 25 mm, and 1 inch. As others said if you're going to replace the pulley as well, it's not critical.
mk378 is absolutely correct. You CAN'T just bolt a standard vertical shaft lawnmower engine onto this machine. The engine needs to be specifically meant for a a machine other than a lawnmower because it will have a cast iron flywheel when it is used in these applications. The best bet for this machine is to find someone who can fix it properly. I have never been a fan of the Pulsa-Prime carburetors, but they CAN be made to start reliably. Before I would replace the engine, I would try to find an autochoke Pulsa-Jet carb and fuel tank from an older 3.5 hp Briggs to rebuild and use (it has a metal carb body and a mixture screw, it will bolt right on the engine). Use 100LL in it after it is fixed.
 
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Originally Posted by jhellwig
Did you try a new spark plug?


Very early on I did the new plug thing.
 
Look up Small Engine Warehouse. They have several different takeoff engines that are new and have some that size with heavy flywheels and adjustable throttle usually.
 
I have a 1981 3hp (last year they had points), didn't realize it had points until we checked and replaced the original set when it was over 30 years old.

Originally it had an automatic choke and would start within 2 pulls. When the carb had to be replaced by a newer primer Button model it would then start first pull and just run a little rough for 30 seconds.

I ended up bending the rod or crank when it hit a huge bolt in concrete under some tall grass and weeds. A major loss to me, it still ran great until that and didn't smoke or use much oil. I replaced it with a 99 6hp GTS b&s. Also starts first pull but it smokes on startup and smells more than old one did.
 
I have a few pieces of small engine equipment around. Some get used infrequently. If one does not want to start I spray a little starter fluid (with a lubricant). Usually starts on next pull. I normally add a dose of Sea Foram in the gas tank after the engine starts.
 
Originally Posted by ChadHubbard
I have a few pieces of small engine equipment around. Some get used infrequently. If one does not want to start I spray a little starter fluid (with a lubricant). Usually starts on next pull. I normally add a dose of Sea Foram in the gas tank after the engine starts.
This is a piece of equipment being used at an airport and the OP has access to 100LL gas. That is all he needs to put in his fuel tank, no additives will be necessary. 100LL has a shelf life of at least 7 years.
 
OK by me. Seems you got your feathers a little ruffled Don't know why. Talk of cleaning / replacing the carb suggests to me that their may be corrosion or gunk.
 
Just an update, I picked the tug up from the shop, declared fixed. They did a bunch of carb, fuel, primer, & other work, even including a new boot & wire to plug.

I started it twice, let it run some. I'll at least start it every two weeks, letting it run some. Yes, I use 100 LL fuel, with some non-ethanol regular mixed in.

The $100 was better than $2k for a new tug, especially with how often it's called into action
 
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