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Discussion Starter · #1 ·
This 5 HP B&S model 1352120006 typical go cart will not pull over due to internal engine issue. The engine will only start and run for 10 seconds if I pure gas in carb too. If I drip gas down the pulsa jet carb at idle it will continue to run for 2 mins then dies. I replaced the fuel pump diaphram and spring 2 times both carb and tank are spotless. I have blown air into a full tank so the pickup tube is OK. Maybe this intermitent engine lock up and no start due to no gas pumping into carb are same. The flywheel key is perfect and nothing under the flywhell causing this lock up. When I turn the belt driven clutch shaft both directions then the engine turns over for 6 more starts then will lock up on next pull. I do not hear any rod knock or valve noise when engine runs. Please help so I can get some sleep and make a girl happy again. Can a camshaft or crank be partly broken and cause out timing issues? The piston did not looked scored.:wave::wave:
 

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Have you tried removing the recoil and turning the flywheel by hand to eliminate a bad starter? I would remove the spark plug and try turning the engine by hand.If the engines runs two minutes and there are no unusual noises,I wouldn't think there is something wrong internally.
 

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Could have carbon build up on the piston causing the lock up, would have to pull the head off and have a look.
 

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Discussion Starter · #4 ·
Thanks for replys

I did remove the recoil and the engine does not turn over still. If I turn the clutch / flywhell nut back and forth the engine does start to turn again. I can feel something hittting inside the engine - could govenor link be hitting camshaft or teeth on cam going bad to mess up the timing so engine will not start on choke? I removed the head and piston looks great - no carbon. Any mores ideads needed before I pull engine off to tear down.:eek:
 

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Discussion Starter · #6 ·
Mike - You da man !!

:thumbsup:I think we are on right track. The engine code is 93043027 and model 1352120006 for the 5 HP. I found the older vertical lawnmower engines used a nylon camshaft but I can not find if the older horizontal also used nylon before switching to a all steel cam pn 691164. Before I go over and pull the front cover can anyone tell me if this engine used a nylon camshaft? This would explain why it only starts on gas poured in carb ( timing off ) and why engine locks up will not pull over ( gear binds on lobes ) on occasion. Stay tuned I will let everyone know what I find.:thumbsup:
 

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a lot of briggs engines use plastic cams also some honda's. they have a steel core pressed into plastic. as an old auto and truck mech, I have seen it all. A lot of auto engines have plastic coated cam gears. briggs cams seem to crack at the shaft where they are pressed on.some engines will turn one way but not the other.take it apart and look hard at the cam & gear for cracks. mike
 

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Discussion Starter · #8 ·
I will check compression FIRST in Future

I found the piston / cyl. wall scuffed and exhaust valve was sticking open. sometimes. They caused the engine not to start by closing :thumbsup:choke and to lock up on occasion. Compression was only 50 psi but since I got it start on gas poured in carb I thought engine was good. Going foward I will always check compression first if no start. What is min compression psi for 4 stroke and 2 stroke engines you guys have noticed? I find many 2 stroke trimmers / blowers/ chainsaws with good spark and good fuel poured into carb but engine will not even pop one time to start = low compression I expect.
 
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