# Briggs and Stratton surging problems



## bsbretly (Sep 16, 2009)

I have a BS 135202 with a pulsa jet tank mounted carb on my go-kart. The engine was "surging" or "hunting" at full throttle. I would be at full throttle and it felt as the throttle was temporarily released (which it wasn't) then it would immediately retain full power. This process would repeat intermittently. I disassembled the entire carb and soaked it for 30min in chem-dip carb cleaner, hit all the jets/passages with compressed air, and got rid of all visible dirt. I reinstalled the carb with new gaskets and the problem persists. Any ideas? I thought it could be the idle mixture screw, but adjusting that didn't seem to help. Please let me know what the issue could be. Thank you.


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## hd4ou (Aug 25, 2009)

did you replace the diaphragm on the side or just put it back in? if you didnt replace it then you need a new one.


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## bsbretly (Sep 16, 2009)

hd4ou said:


> did you replace the diaphragm on the side or just put it back in? if you didnt replace it then you need a new one.


Yes I replaced the diaphram, the tank mount gasket, and the intake gasket.


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## hd4ou (Aug 25, 2009)

Maybe water in the tank? did you remove and drain tank? also those tanks are bad about rusting. once they start rusting there is no stopping them. will have carb problems from now on.

http://outdoorpowerinfo.com/repairs/briggs_pulsa-jet_horiz_fixed.asp


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## bsbretly (Sep 16, 2009)

hd4ou said:


> Maybe water in the tank? did you remove and drain tank? also those tanks are bad about rusting. once they start rusting there is no stopping them. will have carb problems from now on.
> 
> http://outdoorpowerinfo.com/repairs/briggs_pulsa-jet_horiz_fixed.asp


Yes I drained and cleaned the tank, added fresh gas and it didn't look to have much rust in it.

Looking at a diagram of the linkages for my engine, I have notice that the bell crank is not connected to throttle (as I have the throttle connected to a throttle cable hooked up to the gokart pedal) so the bell crank it unhooked from the throttle and doesn't move during use of the engine. Is this a problem? Also could there be something wrong with my governor linkage? Switching the setting from idle to fast doesn't seem to change the performance of the engine. For the parts I'm refering to take a look at this link: http://www.small-engines.com/5briggs.html


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## hd4ou (Aug 25, 2009)

well now i guess i am a little confused. if it was running fine before and this problem appeared outta the blue then i would say the carb still has an issue as far as having some type of obstruction and needs to be clean again. if you just got this engine and it has done it since you got it it may also be the linkages are incorrect.


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## bsbretly (Sep 16, 2009)

hd4ou said:


> well now i guess i am a little confused. if it was running fine before and this problem appeared outta the blue then i would say the carb still has an issue as far as having some type of obstruction and needs to be clean again. if you just got this engine and it has done it since you got it it may also be the linkages are incorrect.


It just started when I tried to fire it up after being dorment for several months. Before it ran fine. I was told there were some jets behind the smaller welsh plug of the carb, is this true? Also, how is the smaller welsh plug removed?


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## hd4ou (Aug 25, 2009)

http://outdoorpowerinfo.com/repairs/briggs_pulsa-jet_horiz_fixed.asp

take a really good look at this link again. everything about your carb is in there including the small holes behind the welch plugs. I drill a small hole in them and pry them out. be very careful drilling as there is very little space behind the welch plug and you dont want to drill into the body and screw up one of those holes. still think it just needs to be cleaned better.


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## bsbretly (Sep 16, 2009)

hd4ou said:


> http://outdoorpowerinfo.com/repairs/briggs_pulsa-jet_horiz_fixed.asp
> 
> take a really good look at this link again. everything about your carb is in there including the small holes behind the welch plugs. I drill a small hole in them and pry them out. be very careful drilling as there is very little space behind the welch plug and you dont want to drill into the body and screw up one of those holes. still think it just needs to be cleaned better.


Would spraying some compressed air in these holes behind the welch plug be sufficient? If not, how should I clean them out? Thanks for the help.


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## hd4ou (Aug 25, 2009)

spray some carb cleaner through them. run a bread tie wire through them. then blow some air through them.


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## bsbretly (Sep 16, 2009)

hd4ou said:


> spray some carb cleaner through them. run a bread tie wire through them. then blow some air through them.


Alright, thanks. What is a "bread tie wire" and where could I get one? Thanks.


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## hd4ou (Aug 25, 2009)

um, the little twisty thingy on a loaf of bread.


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## bsbretly (Sep 16, 2009)

hd4ou said:


> um, the little twisty thingy on a loaf of bread.


haha oh ok. Thanks.


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## bsbretly (Sep 16, 2009)

Just wanted to post an update: I replaced the welsh plug and cleaned out the jets behind it and I the engin runs a lot more smoothly. Thanks for all the help. I might replace the larger welsh plug on the back of the carb as well too.


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## hd4ou (Aug 25, 2009)

thanks for the update.:thumbsup:


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