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Discussion Starter · #1 ·
I am attempting my first engine swap!

I bought this B&S engine to swap. I think I can make it work but am having trouble matching up electrical - alternator, flywheel etc on the B&S.

I believe the B&S engine came out of an JD LA125 with a 5 or 9 AMP alternator. I looks like the JD LX280 has a 15A alternator.

1. It appears I can get a Large Magnet Flywheel for the B&S, but I can't find the part number. Are all B&S Flywheels interchangeable?
2. Beside that it looks like I need a new regulator (10 or 16amp).
3. Do I need a new alternator? I can't tell if there is a different one or if the alternator is fine if I upgrade the flywheel and regulator.

Am I even on the right track here? Any help would really be appreciated. I apologize if I have not used the correct terms in the correct place.
 

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That 330000 series Briggs Intek probably has a "Tri-circuit" alternator (Briggs part #696457). Here's a link that will give you more details and includes some insight into your questions about Briggs Flywheels/magnets at the bottom of the page. The problem with the smaller 9A alternator is the draw from the electric clutch. LX280 with the Kawasaki v-twin ran a much larger 500cca group 51 battery, than the Briggs Intek which ran a standard U1 (340 CCA tops).

What was the problem with the Kawasaki engine? To be honest with you, you're swapping a pretty good engine for a notorious POS. I can show where to get the parts to do a re-ring with new valves on that FH580 for less than $150 if the cylinders mic out to still be able to run standard rings and it's just a little tired. Way less headaches/labor time to do a re-ring/valves than an engine swap.....

Briggs Alternator Chart
 

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Discussion Starter · #3 ·
I bought the LX280 new. I have had nothing but trouble with it and the kawasaki engine. The kawasaki engine has never run very well. When I bought it I knew nothing about tractors and small engines and have learned a lot over the past 15 years. I have stopped short of tearing an engine down and engine replacements. Time to jump into that I guess.

The engine always surged. After about 6 years it lost power. Turned out to be the fuel lines and fuel pump. I figured that out after the dealer soaked me for another $700 without fixing the problem (They did some sort of top end rebuild?). For the past 5 years it has been burning a lot of oil. I was putting a quart in after ever two mows (about 4-5 hours). Once in a while I would start it and thick oil would spray from the exhaust. Currently it does not start. It cranks but does not turn over. I did the normal tuneup stuff but have not troubleshooted since I am heading down the new engine route.

As far as the B&S engine goes, can't I add a 10 or 16 amp alternator and get a flywheel with the larger magnets? I have the document you included (thank you!) It am still not clear on the alternator. It looks like I may be able to keep the same one and just add the flywheel. Problem is, no part number for the flywheel. I do see the 10A option is listed for the 330000 series. I do not see it listed under the 16A option.

I am not apposed to trying a rebuild. I know nothing about it so not sure how successful it will be. I am able to research and apply what I learn pretty well so it does not seem impossible.
 

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"It looks like I may be able to keep the same one and just add the flywheel"

You are correct in thinking the way Briggs ups the ultimate amperage output through the rectifier/regulator is the size of the charging magnets. Small magnets measure 7/8 x 11/16, Large magnets measure 1 1/16 x 15/16. Your 331877-0113-B1 with the "tri-circuit" could have either.... Small magnets 5A(28V AC), Large magnets 9A(40v AC). Uses alternator #696457

Changing to Alternator 696458.... Small magnets 10A (20V AC), Large magnets 16A(30V AC). Be aware of the different ring gear/starter configurations..... Plastic ring gear--- Plastic starter pinion, steel ring gear, steel starter pinion.


The whole point of the alternator specifications is to be able to meet the demands of the electric clutch. That FH580 Kawasaki V-twin runs a much stouter clutch than the Briggs Intek you want to swap. Which clutch are going to use? Clutch off the LA125 should work fine with the existing alternator setup on the Briggs engine. Kawasaki clutch on the Briggs engine is going to be a problem because of higher amperage draw.

 

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Take it apart, measure stuff, replace the worn out stuff, put it back together just like you took it apart without having leftover parts..... Is that too vague an answer?😃

Here's a You Tube video of a guy that has a couple of teenagers tear down a Kawasaki engine. He doesn't know anything, the kids know just slightly more, but they do manage to get the engine apart and down to the pistons sitting on a bench. These kids are sloppy as hell and have no clue about "layout sequencing". That's the difference between a professional mechanic and amateur. Given the time and the tools, even these kids could take the Space Shuttle apart, but that's not fixin' it.... It's putting it back together that determines if the disassembly process turned out to be a tear down, or actually a scrapping.

Watch this video and let me know if it looks like something you want to talk about further. "Layout Sequencing" is disassembly techniques that insure reassembly is smooth and correct and there are plenty of guys on this Forum that can help you with that. The Kawasaki Factory Service Manuals are some of the best out there and they are also readily available on this Forum. You probably are going to need to buy some tools at Harbor Freight, or Amazon..... Inside bore gauge set, digital vernier calipers, inch Lbs torque wrench. Don't need Snap-on quality, $50 bucks tops. The 2nd link is to the cheapest place I know to buy Kawasaki engine parts at retail pricing. 13008-6060 is your standard ring set part #... Do a little on line searching and compare their pricing to others. Bear in mind, these are genuine Kawasaki parts, not Chinese aftermarket. Total in parts and tools should be around $200-$250 if the cylinder bores measure less than 74.1 (2.9289). You won't know that until you tear the engine down and measure the cylinder bore wear dimensions and that's why you'll need a bore gauge set and vernier calipers. That engine sells new, with warranty, starting at around $1,700 + shipping

Knucklehead Garage in Action

FH580 Ring set - Genuine Kawasaki
 
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