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Discussion Starter · #1 ·
My 14 year old son is interested in learning about engines, so we are tearing apart an old (30+ years) mower with a B&S engine. There is no spark. What are some tips on troubleshooting? What is the condenser for? Can a bad condenser stop the spark? Any good websites that explain four-stroke internal combustion engines?
 

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That's great that you're teaching your son about engines!!

Here is a great place to start for all about how an internal combusition engine works:

HowStuffWorks "Internal Combustion"

If you have the model of your engine, you can search it on B&S's website and find the original manual for it that should have all the specs on it like what the point gap should be and other things like troubleshooting tips etc. Manuals | Customer Support | Briggs & Stratton

I would start first with cleaning the points and going from there. If there is still no spark, I would venture to the condenser as they are cheap and your local Napa auto parts store may even have one in stock. The condenser in a nutshell stores the charge from the mag until spark plug is "told" to fire by the opening of the points.

Keep us updated on the project! :cool:
 

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Discussion Starter · #3 ·
Off to a great start... figuratively!

Well, we got it disassembled down to the last nut and bolt... except for the valves/springs. Got any suggestions of a tool or secret way to get them apart?!?!?!?

Points "appear" to be OK. I think I have an old tester from my Dad which tests condensers...? For the price, we will just replace the condenser anyway... but since this is a teaching experience, I would like to show Bradley how to troubleshoot with tests, as opposed to just replacing parts, when and where I can.

We can't find any identification on the engine for type/model/etc. Got any suggestions there??? We will need at least a gasket kit... and will possibly replace rings while we are at it. Otherwise, the old engine looks pretty good. No noticeable scores on cylinder wall, journals, or cam.

What a great base to teach from! Bradley is already grasping the difference between a 2-stroke and a 4-stroke engine. Your recommended website to HowStuffWorks will be very helpful.

If I did it right, there should be a picture attached of Bradley with the engine in a million pieces.
 

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That's fantastic!! It sounds like you guys are having a lot of fun while making it a great learning experience as well.

I am not sure what model it is specifically from viewing the pic, but it does look like it's says 3.5hp if that's the shroud for it. If nobody else here knows the exact model, I would ask on either SmokStak or on the ASECC site as someone at either of those places will know for sure. Chances are, you will probably even be able to buy a gasket kit from B&S as it doesn't look like it's too early of a model.

http://www.smokstak.com/forum/forumdisplay.php?f=27
http://www.asecc.com/

Regarding dissassembly of the valves and springs, you will want a valve spring compressor tool. Briggs lists a part number for one on there site for this purpose: part number 19063

Servicing the valves | Frequently Asked Questions | Customer Support | Briggs & Stratton
 

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Discussion Starter · #6 ·
Numbers found!

Found model number right where you said it would be. Thanks!!!
 

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Discussion Starter · #7 ·
Progress... sorta!

Not sure how long people follow subjects here, but here's my update:

B & S responded to my recent on-line inquiry... very helpful. Ultimately found exploded parts diagram, etc. Also found, and ordered (don't tell my wife) valve spring compressor, piston ring compressor, and complete gasket kit.

Y'all heard of Lisle Tools? They seem to have a lot of tools for this sort of project.

Soon, son and I will be back out in the barn finalizing the disassembly. We need to clean everything real good. Meanwhile, son has been checking out How Stuff Works, etc... acting like he is cramming for a final exam or something!

I have not been able to find specs... like ring end-gap limits, bearing tolerences, compression value, etc. These things might not be critical to what we are doing, but this is a great opportunity to teach son how to measure things, how their tolerences/specs interact, etc. If anyone can steer me to specs, PLEASE DO !!!

This is very cool... reminds me of when my Dad used to teach me things out in his garage. Of course, no "How Stuff Works", nor any other website/internet stuff back then!
 

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You bet we like to hear how things are going! Sounds like things are coming along great for you. Keep in touch.
 

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It's great to hear your doing this with your son. My grandfather did the samething with me when I was 12. I'm 35 now and still woking on them. The guys here are great and will take care of your questions.
 
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