briggs 11hp carb pops!

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  #1  
Old 09-30-03, 04:57 PM
jada
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briggs 11hp carb pops!

asking for troubleshooting tips, have adjusted carb, valves are gapped ok, new plug, what would make my lawnmower backfire thru the carb? this mower has set up in barn for some time, reset screws, and tuned, turns over and almost starts but then backfires thru carb. any new ideas? thanks a bunch. jada
 
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  #2  
Old 09-30-03, 05:37 PM
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You said that you cleaned the carb. Did you clean it all the way? There are many pieces inside of a carb that can get dirty. Another thing that can cause the backfire is adjusment of the carb. You may have adjusted it wrong. If there is a bowl screw on the bottom of the bowl of the carberator, than tighten it all the way, than back it off 1 turn. Then try to start it. Another thing is to make sure your fuel line is clean and the the gas tank is also clean. Another good thing to do is fill the tank almost all the way up with gass and put 3 cap fulls of additive in the gas tank. Do all things and you should get it to start. If it still does not start, then you need to look into the possibility that it needs a new coil. LEt us know how it goes...
 
  #3  
Old 09-30-03, 11:33 PM
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Hello jada!

Welcome to the small engines forum!

How old is this engine? (trying to determine if it has points, or electronic ignition).

There are lots of possible reasons for the backfiring. One could be carb flooding. Look at the plug. If it looks wet, it is probably flooding and replacement of the float and/or needle would be the cure.

It could be an ignition problem, especially if this engine has points.

Another possibility is an intake valve clearance too tight. How did you adjust the valves?

A stuck valve could also do this.

Restricted exhaust can do this.

A sheared flywheel key will definitely do this, it is a common problem on engines that have come to an abrupt halt (like hitting a stump with a push mower blade), and on engines that have had the flywheel removed and re-installed.

Another possibility could be incorrect cam timing (if someone has been into the engine and didn't time it before reassembling).

A loose/bad valve seat can do this as well.

If you don't know how old the engine is, post the engine code# and I will tell you. It is stamped on the engine shroud, just above the spark plug. The code is the 3rd set of #s.

Does the engine have good compression? If so, it would help steer us away from valve problems.
 
  #4  
Old 10-02-03, 03:19 PM
jada
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Terminator 20 and cheese, thanks for your advice, i've been working on this for 2 days, ha. i checked valves, clearance, sprayed carb cleaner in carb and valves, so see if sticking. i also turned in carb screws, then backed out 1 1/2 turns, the bowl however if tightened down, then backed out fuel started seaping.

but while checking out those suggestions, i found another prob which is a wire hanging from under flywheel. at first the mower turned over and even started but died quickly but i think i may have broken wire not meaning to.

tracing wire down, i pulled flywheel off, the outside ring of windings was burnt, but that was another prob, i dont know how that is wired. i assume start switch, but tail end wire from windings burnt without trace of where it was connected.
the other wire hanging i found 2 wires from points, 1 goes to magneto, the other is the one that is hanging outside about 6-8 inches length. i dont know if this wire should be grounded, or if it went to magneto. im sure in an awful mess and it aint getting better, ha. can you guys tell me exactly the wires from the point plate connect to? and the winding wires and how it connects.

thanks, tried to write short and brief as possible. jada
 
  #5  
Old 10-02-03, 11:33 PM
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Heres your best bet: Just forget the points and install another coil with the electronic module built in. It is basically trouble free and much more accurate than the old points. It takes no adjusting or maintainence, unlike points. This may solve your running problem altogether.

Your alternator windings are burnt. A new alternator is needed. The red wire will connect to a battery source. If it has 2 wires from the alternator, then the black wire will connect to the headlights.

You should be able to get both of these parts used for little $$. These parts can be obtained from most any 1 cylinder briggs engine from the 10 to 16.5 HP range.
 
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Old 10-03-03, 03:52 PM
jada
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Thank you so much, and i traced my wiring down, red and blk are connected as you say. i will replace the windings, and i will go with electronic ignition. Again thanks for your help, i much appreciate it. Jada
 
  #7  
Old 10-04-03, 12:10 AM
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Anytime! Let us know how it goes!
 
  #8  
Old 10-07-03, 07:06 AM
madsam
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the snowblowers i am working on, are old , and i would like to know if anyone has a link to info on the electronic ignition you guys are talking about. most of these are tecumseh 7 hp engines. some look old, and some look real old...lol.

we are going to work out the codes and model numbers and try to narrow down how old they really are, but they are all points/condenser setup.

i would also like to know if it is easy to add an alternator and battery to these engines, without having to replace any existing parts, such as a flywheel, for example. i have one with an ac starter on it, and the others have teeth on the flywheels to accept starters, and we would like to use dc starters instead of ac.
 
  #9  
Old 10-08-03, 12:34 AM
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A D/C starting and charging system is MUCH more difficult and expensive to install. D/C systems require a battery, solenoid, keyswitch, charging stator, more wiring, and new flywheels. Actually, if these engines all have points, then I don't think there is a dc charging system for these older style engines. I could be wrong...can't remember. I think the electronic atom modules will work on those older tecumsehs. If you decide to go with the points, there is a lot of work involved in obtaining the correct setting, and a manual would be the best bet. It is a fairly complex procedure for setting the timing on these, unlike most other engines.

I would go with AC starters...simple and easy and inexpensive.
 
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Old 10-14-03, 07:34 AM
madsam
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cheese, are you suggesting the older tecumseh engines with points/condenser are a bit difficult to adjust and set up, especially for a new guy like myself? if so, it would be great if someone could please post a link to those electronic ignitions, as i would love to go that route instead of the old points. the issue is that these are old engines, and those with spark have fairly moderate, to weak spark, so, we would have to replace the points/condenser/and possiblly coil on most of them. for the first few we will fix, we will be using these urselves , and we therefore want to have the most reliable option, and electronic sounds sweet to me.

anyways, i need a link to these electronic ignitions. i have seen several of them online, but there are several brands, and i have no idea what is what, and who's got the right ones , cheap...
thanks....
 
  #11  
Old 10-15-03, 01:06 AM
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I'm not sure which ones will work with those particular engines. They are kind of excluded from the list of atom chip applications, so there may not be an atom chip that will work on those engines. I would guess that the blue chip #AM-207 would be the closest one, but they say that it is not reccomended for use on cast iron flywheel tecumsehs...which is what you have...so...??? Maybe there is another company that mfgs those modules for the engine you have. If you just need to change the points and condenser, it is not hard or complicated, but don't loosen the metal bracket that they are bolted to. Leave it alone and just replace the points and condenser. If you need to replace the coil, then you get into an involved process. Do you have a small engines manual? You can pick up a haynes at Advance auto parts for cheap, and it will help you with setting up the ignition on these things. A tecumseh manual would be better, but for what you're doing, a haynes would be fine.
 
  #12  
Old 10-15-03, 06:22 AM
madsam
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cheese, i have purchased a few manuals of different types, but one is a chilton's manual. i have a tecumseh manual coming soon, but i think it's for "L-head" engines. i'm not sure if my engines are considered L-head, or overhead valve. seems the valves are up top, but i'm not sure if that is overhead valve or not. when browsing for manuals, i see several different ones. could you direct me to the correct tecumseh manuals i need for these older tecumseh's? for instance, one is from 1986, and the other is from 1979. i agree these have cast iron flywheels.
 
  #13  
Old 10-16-03, 12:22 AM
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Your engines are "L" head. OHV engines have the valves in the head, not the block. You will need tecumseh manual #692509 3 to 11 hp 4-cycle L-head engines.
 
  #14  
Old 10-16-03, 06:24 AM
madsam
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cheese, i bought a similar manual. my manual is "740049" which covers "L" head engines from 3-10 hp 4-cycle. i believe the manual you referred me to is a newer version of mine, since my book says copywrite 1998. the newest manual also includes the 11 hp, which i don't need. i got this manual for 3 dollars on e-bay, plus shipping, of course. i must admit, tecumseh puts out a decent manual, and seems to cover more than needed.

thanks for verifying i did buy the correct manual, as the OHV idea confused me a bit.

i'd also like to mention that i found the atom ignitions, and the one meant to fit tecumseh specifies it doesn't work with tecumseh engines with cast iron flywheels, which , i believe is the flywheels our engines have. looks like i'll have to learn to adjust and tune the ignitions on them instead of going with electronic. thanks for the tips on this also, as i almost bought one, which wouldn't have worked.
it, however, might fit one of the engines we haven't worked on yet.

 
  #15  
Old 10-17-03, 01:21 AM
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Good deal...sounds like you have the right manual.
 
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