6hp, 1974 fuel dripping out carb

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

yeah, i believe it is a rubber tipped needle, i think it is sealing though

Another weird thing happening is that the fuel leaking out has a brownish color to it.

Well progress was made this afternoon...I took the carb off again, readjusted the float, double checked the needle...and on and on.

pulled the flywheel , double checked the points and timing all ok

put back together got it to run and still had gas leakin out but not so bad and eventually it turned bluish so that mystery was solved. I guess there was just still carbon in the fuel line.

The big discovery was that the fuel pump wasn't working. It would pump a little but not enough to keep the carb bowl full, so while i was tweaking the idle thinking the fuel pump was okay the bowl would run dry and the motor would stop. So after i found that out i just kept pumping the bulb to keep the motor running and tweak the idle. I got it to run pretty decently as long as i pumped the primer bulb.

So here is the fun part....I was thinking maybe the fuel pump wasn't getting pulsed by the motor pressure changes, so i took it off and held my thumb over the hole on the power head to see if i could feel any pulses and started the motor. When i pulled my thumb off the hole, fire shot out that hole and toasted the end of my thumb! Not bad, just enough to get my attention, so i guess there is some pulsing happening there.

 

[tillyd]

Re: 6hp, 1974 fuel dripping out carb

hi , seems to me you've done everything possible have a look at this site all about small johnson's at;
www. sschaptersa.com / leeroys ramblings , hope it helps as it did for me.

 

[tillyd]

Re: 6hp, 1974 fuel dripping out carb

hi , congratulations what a relief at least its not a carb problem and fuel pump filters are cheaper than carb parts !

 

[the machinist]

Re: 6hp, 1974 fuel dripping out carb

OK guys, I now have my own website instead of going thru www.sschaptersa.com & that link may now be dead, however I relinked it to my new site. If you can't get it from there, try my new website www.leeroysramblings.com that I just activated yesterday after a while of debugging the data transfer.

My guess is that your rings are not sealing good enough to not allowing enough vacumm to pull the fuel into the crankcase, (possibly your fuel leak also) also evidenced by fire coming out the crankcase fuel pump hole (also bypassing the rings). Maybe a time to decarb the engine & hope it will loosen the stuck rings, other than that, a re-ring job.

Good Luck LeeRoy

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

OK guys, I now have my own website instead of going thru www.sschaptersa.com & that link may now be dead, however I relinked it to my new site. If you can't get it from there, try my new website www.leeroysramblings.com that I just activated yesterday after a while of debugging the data transfer.

My guess is that your rings are not sealing good enough to not allowing enough vacumm to pull the fuel into the crankcase, (possibly your fuel leak also) also evidenced by fire coming out the crankcase fuel pump hole (also bypassing the rings). Maybe a time to decarb the engine & hope it will loosen the stuck rings, other than that, a re-ring job.

Good Luck LeeRoy

Yeah, that makes alot of sense, wasn't sure why fire would shoot out that hole. I thought maybe the sudden rush of oxygen when i took my thumb off, but blowby the rings seems more plausible. I was suspecting the rings were possibly bad with this motor. I'll try and decarb and see what happens. I soaked the tops of the pistons pretty good with seafoam when i had the head off to replace the gasket so i'm not getting my hopes up with a decarb...

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

Well i did a semi-decarb. I only had a few ounces of seafoam so i poured it directly into the spark plug holes and let it soak for an hour or so. I had the pistons in the middle of their stroke so the sea foam just sat on top of the pistons and eventually soaked thru. After i started the motor it would idle much better and seemed to run longer before the carb went dry. Also i didn't have nearly as much fuel dripping out the carb throat. It looked wet but fuel wasn't pooling there. I'm going to buy another can of seafoam and do a real decarb and see what happens.

Regarding the fire shooting out of the fuel pump hole in the side of the crankcase...Is it possible the ignited mixture just took the path of least resistance and blew by the rings and out that hole instead of the exhaust ports???

 

[geoffwga1]

Re: 6hp, 1974 fuel dripping out carb

Here's another silly question. Did you by any chance blow the tiny rubber needle seat out when you cleaned the carb.I did that once and it took me about a week to figure out what was wrong.They are very small and hard to find if you blow them across the workshop.
Geoffwga1

 

[scott_maier]

Re: 6hp, 1974 fuel dripping out carb

Here's another silly question. Did you by any chance blow the tiny rubber needle seat out when you cleaned the carb.I did that once and it took me about a week to figure out what was wrong.They are very small and hard to find if you blow them across the workshop.
Geoffwga1

The seat is brass, the needle is stainless with a rubber tip. I'm guessing you mean the needle, and no it's still there...that would definitely create a flooding situation if it was gone!