Briggs & Stratton 8 hp - won't start

Dirt Bike Dan · Jun 13, 2005

Don't know much about it. It's 8 hp, horizontal shaft, from a go-cart. It has good compression, spark, and I know gas is getting into the carb. I had it running last year, but not very well. I replaced the ignition system (points, spark plug, etc) Then it slowly got worse (kept dying) and then wouldn't start. The flywheel key is good. I cleaned the carb last year. I'm going to clean it again, but I'm almost positive that isn't the problem. I can get it to fire, and even idle for 10-15 secs. If i touch the throttle, it dies...if i don't, within a couple secs it dies. I'm out of ideas. My only guess is something with the governor/linkage or timing chain? Anyone have any ideas or experience with this type of engine/problem?

Joe Diver · Jun 13, 2005

Choke stuck?

Dirt Bike Dan · Jun 13, 2005

nope choke works fine (no air cleaner on it right now)

dklink2000 · Jun 14, 2005

If I had to guess I would say it is the carb. Had the same problem on a honda lawnmower last year. It sat for several years with no storage prep. I took the carb completely apart and cleaned it. After that it would start but not run. I finally gave up, and put a new carb on. It has been purring ever since.

Crash217 · Jun 14, 2005

put the air filter back on, and make sure it's clean... leaving it off is giving you a really lean setting and is going to make it not want to run. using a dirty filter will give you a rich setting and it won't run properly their either with stock jetting.

I know it sounds really silly, but do you have the right amount of oil in the crank case? being a small engine mechanic (lawn equipment, go karts) I've seen some really whacked things people do to their engines.

take the engine model number down to the local briggs shop and get a carb rebuild kit... you'll get all new gaskets and seals with it. that will help a lot.

If the governor settings were off it'd either fire instantly and death rev or it wouldn't try to idle at all. I'm doubting there's a timing chain it there... it's probably a flat head design with a cam running off the crank via a gear. then the cam bumps some lifters that in turn move the valves.

get the model number of the engine and do a search for briggs engines on the web. you should be able to find parts diagrams and all sorts of info.

Dirt Bike Dan · Jun 14, 2005

ok thanks for the tips. I'll have to see what happens, hopefully I can get it running.

bikepilot · Jun 14, 2005

Yep, its a flat head. I had one on my Manco Dingo Go cart, loads of fun:)

Sound's like the carb is pluged, when you open the throttle more air gets through and its leaning without more fuel. Also check that the carb has good fuel supply.

good luck

triden · Jun 15, 2005

if you turn on the choke and and rev the trottle will it run? Also is the sparkplug black in any way? This will help you decide if the carb is running too lean or too rich

Dirt Bike Dan · Jun 16, 2005

I got it to run, and hopefully I can get the carb tuned this weekend. Strangest thing I've ever seen, I couldn't get it to run without an air cleaner on. At first I couldn't find it, so I pulled the carb, cleaned it, checked for obstructions in the intake tract, and set the carb adjustments to stock settings to try and get it to run. Nothing. A couple sputters, even with starting fluid, but couldn't keep it running. Choke on/off, didn't make a difference. The spark plug was dry, which really perplexed me, because I was certain it was getting fuel into the carb. I was out of ideas, so as a last resort I grabbed the air cleaner of my quad and zip tied that on - presto, started right up. Anyone know why it made a difference? I tried adjusting the carb a little richer when it didn't have the filter on, but it wouldn't start. Oh, when it did start, i had the governor linkage disconnected (if that makes a difference?). Situation just seems strange to me.

maddmack · Jun 16, 2005

on most b&s there is a hole right thought the carb where the air filter screw gose into the carb.the venturey of the carb will pull fule though this hole.and there for to much gaz.so just replace the scerw with out the air filter if need be when tuning but always better to tune with a completely assembled motor.

Briggs & Stratton 8 hp - won't start

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