Briggs and stratton wont run

[clemsonfor]

After replacing the coil that was shorted out several places in the wire i put my new one in and motor fired right up, ran ok for a 30 yr old engine. cut it off and back on fine. Later that evening i went to restart it and it would not. Kept going through everything respaced the coil, but i had spark both times. Sprayed carb cleaner in to make sure i was getting fuel and no go. Pulled the carb and looked through it, put back on and readjusted to factory settings no start. So i pulled the head to have a lookse. Problem found the valve seat on the exhaust valve was loose and hanging aroung the shaft of the exhause valve not letting it close so i have no compression.

Question is this something that can be pressed back in? Fairly economical? This is a 30 year old briggs engine, rings have wear as it smokes, so im not going to throw $200 at it if it can even be done? Reason it came loose? Is the block wallowed out possibly where the seat presses in?

-Nate

 

[jbarker855]

Most of these blocks are aluminum. It is soft enough that you can use a hammer and small punch to stake the seat back in. Just pound at the metal on the block just around the seat to try to get it to stay down. I read about this technique in a Briggs repair manual. I have fixed small engines for many years, and admittedly have only encountered this problem once. I tried the above fix and it didn't work very well. So...this is the best I have to offer you. Give it a try if you don't get any better suggestions. Good luck!
-Jay

 

[jbarker855]

Let me know what you decide to do. I'm curious to hear what happens.
-Jay

 

[clemsonfor]

yep its an aluminum block. Still thinking about it. I did mess with it yesterday, turned engine till exhaust was open and made sure the seat was flush then closed the valve actually had them both closed for the compression stroke, and the exhaust valve has a small say .010-.020 side to side movement it looks like. Meaning i can put my finger on the closed valve and it will move around, the intake is fimly in place? Maybe this is due to the seat not being set or really held in by anything? I opend the side inspection plate for the valves and both assemblies looked the same throughout their motion.

Still seeing if others may have something else. So anybody got anything, yea on this nea, i did this thing once, etc?

 

[psj12]

If this was my old engine and the rings were worn and a valve seat was looseI would replace it. These engines are not that expensive to replace. They are generally available at surpluscenter.com or used from a local small engine repair shop.

 

[oldnslo]

Get some JB weld and clean the valve seat area very well. Apply the JB weld to the block and press the valve seat into the JB weld. Install the valve and spring to hold the seat in place and aligned properly. Let it sit a minimum of 24 hrs. Lap the valve seat if it needs it and fire it up. Have done this on two different motors and they are still running today.

Roy

 

[clemsonfor]

I called the local small engine place asking about rebuilds or short blocks. Since they no longer make it no go. A replacement is $440is. Great price the problem is that is a few hundred over what i wanted to put into this right now, as a second mower. I will not throw this away as it was my grandads and will get it running at some point. The deck is in suprisingly great shape considering, that in my experience the deck usually wears out long before anything else on a mower and usually has welding all over it at that point, this does not. I also have to get 3 tires to replace the dryrotted blownout ones.

Anyway back to what jbarker said the b&s guy at the store told me if you can get a .070 gage in between the seat and valve throw it out, if less do the punch thing, what it calls for. Hey your right i just still find that as a "fix" not really the correct way in my opinion i guess i would have though there would have been an oversize seat and valve i guess?

Anyway he said to let the valve down punch one side then direcly across from it then a pair at 90 degrees to those then continue all the way around till you have a solid ring of punch marks. He said he has done this on several that were worse than .070 and they held for a good while.

You were right on jbarker. NOt that i was doubting you that it would work just like you said it seems kind of hokey to me. Crazy that in the eary 80's (motor i think is a 1980 model) we were making throwaway stuff? :confused2:

-nate