# snapper problems



## miker (Sep 9, 2005)

Hey great site. I'm a new member looking for some expertice on a old snapper 3.5hp lawn mower. Model # 92908 Type 182601 Code 78021028. Here is what it's doing. Once it's running it surges and runs rich with a slight black exhaust. Here is what I did. Disassembled carb & tank (had a little water in it) and cleaned with carb cleaner. Replaced diaphram and reset the choke. Added a new plug C19LM (or something like that) gapped at .030 and put it all back together.
Question, when reassembling the carb does the spring go on top of the tank then the cap. Then the diaphram and the carb on top? 
I started it up and everything runs better but the problem is still there. Now I'm in the process of replacing the needle valve assembly. It showed slight wear but I don't think that is the culprit. I was told that the tank could be warped but I can't tell.I understand that this is an old engine.But I just put on new wheels and found a brand new bag.From what I see on this site it sounds like a trusty engine. Any help would be really apreciated. Miker.


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## bugman (Aug 12, 2004)

briggs 3.5.... auto choke huh? well make sure to use a ji7lm or j19lm champion plug or even better a autolite or ngk equivalent..... actually what i'd do if your not too far into it is find a newer 3.5's tank and carb and swap, you may be able to find a junked or used one at a junkyard, small engine shop, garage sell.....etc, less trouble..... but yeah these tanks did warp but you can check it with a straight edge for warpage... the needle there should be turned in till snug, backed out 1.5 turns then fine tune. but if it had wear, do replace it, it will cause problems. as for it being a trusty engine...... no doubt.


oh and forgot to add. go to the briggs website, put in you model number and get the owners manual... and/or illustrated parts list


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## miker (Sep 9, 2005)

Hey bugman thanks for the quick responce. I fiddled with it last night.I installed the neddle valve.Still runs the same.Chugs and runs real rich. I can screw the neddle valve all the way in and get no change in the performance.When I install the seat for the valve how far down should it be. Tight? When I pulled it out it wasn't screwed down tight.Also, the spring and cap go on top of the tank below the diaphram, right?


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## fords-n-mowers (May 6, 2005)

i hear ya on the newer carb bugman. i like the ones with the primer button even though you cant adjust them they seem to make the older motors run good.


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## bugman (Aug 12, 2004)

fords-n-mowers said:


> i hear ya on the newer carb bugman. i like the ones with the primer button even though you cant adjust them they seem to make the older motors run good.


 i know, i hate that plastic crap but they are good carbs none the less, easy starting and no hassle...




though go in tight on the valve seat.... then adjust the needle, 1.5 turns out from going in snug... then fine tune, while its running and warmed up... though if your up to it......you can find a newer style carb and tank to replace it....


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## jgayle762 (May 22, 2005)

miker said:


> Also, the spring and cap go on top of the tank below the diaphram, right?


The spring and cap actually go on the carburetor side (above the diaphragm).


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## mikemerritt (Dec 6, 2004)

Thats right, its tank, diaphragm, cap and spring stacked up in that order. 

Mike


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## miker (Sep 9, 2005)

Hey Guy's I just want to take a second and thank everyone for thier input. With your advice I was able to find someone with a used carb and tank. The best part is I found a great repairman. Charged me 15 bucks for parts and 15 bucks for labor.It runs much better, but he said if I'm not saticfied he'll put on another one.He also replaced the hub (it was badly worn), sharpened the blade, blew out the crank cover, degreased the engine, powerwashed it and lubed it. thanx


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## bugman (Aug 12, 2004)

was it one of the newer carbs? then that was a great price. 30 bucks in all was a pretty good deal.


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## miker (Sep 9, 2005)

I don't know if it is or not. It looked the same but it didn't have the brass needle valve seat like the original one did. All in all, it runs much better but there is a delay if you punch it from an idle.


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## bugman (Aug 12, 2004)

is it plastic?


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## miker (Sep 9, 2005)

No. The carb is metal. It looks the same but the needle valve he replaced had a plastic sleeve in it


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