Engine won't start

[drawingslim]

Mid run my engine stopped running, it seemed to lean out and then it died. I checked needles, fuel lines, carb and spark plug and all seemed fine. I then took the head off and found a couple of gouges in the piston and the head. Got a new head kit installed it and still nothing. I then pulled the carb off my running 5b, tried it and still nothing. I pulled the coil and fuel tank out of the 5b and tried both of those and still nothing. I cannot seem to isolate any certain part of the motor as the problem area. Tried new plug, coil, carb, head, fuel lines and tank, and even the bottom end. Still nothing. Any help would be greatly appreciated


Thanks, Ryan

 

[Gas Jocky]

Holy crap! I think you covered everything.... If your piston was gouged that was a lean seize. So the only thing I can think of is when you assembled the new top end you may have installed the piston 180 deg out. little dot or triangle stamped in the top of the piston goes to the exhaust side. also check your kill switch. Good luck

 

[drawingslim]

You were right on about the piston being 180 out, I am a retard. Anywho thanks for your help, gunna put her all back together and see if she'll run.

 

[drawingslim]

AAaaargghhh....


Well it's all back in one piece, and it still won't start. I am beginning to think it may be a fuel issue. I have the long tube connected to the top of the carb, and the short tube going to the bottom. When I press the primer it fills with fluid. I can see a visible spark when pulling the starter, but I don't see any fuel on the plug when I pull it out (should there be?) I have the LS needle at 1 and 1/4 out and HS at 1 and 1/2 out. All new gaskets have been installed. Does anyone know the proper clearance for the coil? I have heard .012 but am not sure. I have removed the kill switch completely so that is not a factor.

 

[kun114]

You know the cardboard hanger that comes stapled to HPI parts bag when you get new parts. That is just the right thickness. Just cut a quarter inch thick strip off, and place it between the coil and flywheel. Then tighten the coil bolts.


Double check your carb gasket. The little hole in the carb gasket needs to line up with the little hole on the carb towards the bottom. The little hole on the carb towards the top is a dumby. Hope this makes sence. It can only go on one of two ways. right or wrong. I'm refering to the gasket between the carb and the intake.


Lastly, everytime I've replaced a head kit, it's been a bitch to get started the first time.


You might just have to yank on the cord till you're ready to have a heart attach. For some unknown reason it starts on the second or third pull everytime after that first run.

 

[Sprint 77]

Run your low speed needle all the way in, pull few times till the motor hits a little then turn the low speed out to 1 full turn and try to start it. This helps clean ot the gas in the crankase if it happens to be flooding.

 

[Clubin]

One thing I found when starting a rebuilt engine is to put about 1tsp of oil in the cylinder to help seal the ring till the engine gets running and seats itself in.

 

[Piranha2]

I just had this same issue. I tried running today and only ran w/choke......ok, I know this one already......(headgasket)......but 1st I take apart my carb and clean everything.......start truck up and only runs w/choke........ok, I know this one.......(headgasket)......I take it all apart and within 1/2 an hour, I try to start it.......nothing.....take it apart and check the coil gap, ok.....try new plug, nothing......check for spark, ok.....still won't start........I will try everything mentioned above, but WOW what a beach this time!

 

[hamster huey]

Are your to and from fuel lines correct on the carb? After I was sure they were correct I still could not prime it at the bulb after my headkit. I ended up doing it manually with my mouth and stupid got a mouth full of fuel because I forgot to take the fuel cap off but then I think I pressurized it or cleared the lines or something and then I was able to prime it at the bulb. My check list was headgasket, spark, air, fuel, arrow on piston, and thats all it took me.

 

[Piranha2]

I didn't remove the carb to install the new headgasket, so the lines are ok. I have spark and it was running 30 minutes prior to trying it with the new headgasket. Thanks for the suggestions though.

 

[magnum57]

What motor are you running? Rob from rampage hop ups and I were at dog park running our trucks and buggies and my mt just stopped running just like yours. I was running a brand new CY 28.5. we tried everything just wouldn’t start. We pulled and pulled and pulled. No go. Rob came to the conclusion the motor ran to lean and toasted the cylinder wall. Replaced the top end and ran great ever since. To lean is no good. Very fine line. When tuning I found go 1 ½


H 1 ¼ L to start. Put on the bench start motor go full throttle an adj the H until max RPM is achieved back off and open needle 1/16 more and you should be good to go. Anyway hope you get it figured out.

 

[Piranha2]

Yeah, she was set at 1-3/8 H and 1-1/4 low, I'm thinking it's not a lean seize because it was running just before the gasket change.

 

[Piranha2]

Thank you all for the great suggestions, the one thing everyone of you missed was...........ME.........so I tore it all down completely and went thru every suggestion, double checking all the little details and the one that caught me was when I looked down into the crankcase (in my case, "swimming pool") and saw all the fuel mix, so I wicked out every last drop and carefully reassembled the motor. After a few pulls, I turned the L speed idle screw ALL the way in, after a few more pulls......BURPP.....ahhh, we're close, next pull......pullstart cord breaks.....AAGGGHHHH......ok, back to.......BURPP......turn the L speed needle out 1-1/4 turns, a few more pulls........BURP.....BA-BING....BA-BING.....BING-BING......SOOO, the winner is..........SPRINT77 , Thanks bud! and to ALL who tried to help a donkey in distress....now, I get to go beat the snot out of that PIG!!!!!!

 

[Piranha2]

Thanks Moo, I have yet to retorque my head bolts......I've been busy with my suspension arm holders....I modded the front with a thru bolt and turned all 4 around because they had so much wear from the arms. Picked up a lot of the slop I had in the arms.