B&S 11hp engine question

[handirifle]

OK got the paper off the engine tonight and checked the converter. The main bolt, bolting it to the crank was loose enough to turn by hand, duh! I haven't started it up yet, but I am sure that is the source of the "knocking" noise. What a relief. I feel like a dummy for not thinking of checking things like that out before.

Tonight I got all the parts painted, except the bed, and tomorrow will re assemble the painted parts. I will post pics of the completed unit. I must say it looks about 200% better than before.

 

[handirifle]

Got it together and fired it up and THAT KNOCKING IS GONE!!!! Yipee!

One other issue I have never gotten rid of is it still backfires ans basically seems a bit out of time. With the magnatron system I didn't see any lateral adjustment to allow for timing the spark.

Any suggestions?

 

[Buckshot 1]

:smile: You are correct, there is no lateral movement only up and down for the mag. Check the flywheel key. It maybe partially sheared, throwing your timing off. Also check the mag air gap to flywheel, I set mine at .012". That engine was originally a points engine, someone has either install a Magnetron mag/a magnetron ign. kit on the the original points mag.

 

[handirifle]

:smile: You are correct, there is no lateral movement only up and down for the mag. Check the flywheel key. It maybe partially sheared, throwing your timing off. Also check the mag air gap to flywheel, I set mine at .012". That engine was originally a points engine, someone has either install a Magnetron mag/a magnetron ign. kit on the the original points mag.

I thought so as well, at first. There is no place on the engine where points would mount, and the flywheel cover also says Magnatron Ignition on it, on a factory sticker.
the flywheel is solid, I have had it off and back on. No slop there. Keyway looked good.
can the gap affect timing?

 

[Rivets]

Yes, the armature air gap will affect the timing. Set it at the factory setting of .010.

 

[handirifle]

I am pretty sure that is what I set it at. Dont remember completely.

 

[Buckshot 1]

:smile: After going back and checking the IPL for that engine, I guess it was manufactered either way. Set air gap at .010 like Rivets stated. I always set my air gaps at .012 and never had a problem.

 

[handirifle]

Yesterday I spoke with a local small engine repair guy and he also said he felt the popping is timing related. He uses a business card, LOL, which some here suggested. I am retty certain I set it at .010" but I will be pulling the cover back off and this time I will experiment with various settings to see if/which one clears the backfiring.

Since my laptop died on me it's be

I will let ya know if anything helps.

Its been a real PITA to post msgs let alone pics, so I will have to figure out another way.

On a good note, I got the brake parts back and installed, but just got the valve for the park brake so I have not installed it yet. I also need to find an inexpensive hi/lo headlight switch for the handlebars.

I used a scraper and engine cleaner to clean about 95% of the crud that has accumulated on this thing over the last 30 yrs.

 

[Rivets]

.010 air gap is the manufacture recommendation. Setting the gap at .012 will retard the spark timing and will produce a hotter spark, but also slightly shorten the spark duration, increasing the amount of unburnt fuel, which will cause a popping in the muffler. Setting the gap at .008 will advance the spark timing, producing a weaker spark, and again increasing the amount of unburnt fuel. Hope this makes sense.

 

[handirifle]

Yes it makes alot of sense, I just need to find out why its popping now and find a setting that stos it. If the gap is other than. 010" I will know why, I hope!:thumbsup: