Blowing Fuel Out Intake, No Start

[bugdewde]

I had a 17.5 opposed twin (flathead) doing the same thing ... blowing fuel out the intake/air cleaner upon attempted start-up.
A compression test told me which cylinder was dead (0 compression) . I pulled the head off to find an air cleaner to carb screw was lodged in the intake valve.... holding it open.
This allowed the pressurized fuel mixture to blow up the intake and out the carb.

I simply pulled the offending screw out with needle-nose pliers and it ran like a dream for many years!!!!!

 

[repperl]

I had a 17.5 opposed twin (flathead) doing the same thing ... blowing fuel out the intake/air cleaner upon attempted start-up.
A compression test told me which cylinder was dead (0 compression) . I pulled the head off to find an air cleaner to carb screw was lodged in the intake valve.... holding it open.
This allowed the pressurized fuel mixture to blow up the intake and out the carb.

I simply pulled the offending screw out with needle-nose pliers and it ran like a dream for many years!!!!!

I may eventually have to open it up and see as well. Trying to eliminate everything before doing so.

 

[Scrubcadet10]

Did you see the intake valve bump open when you watched the valves?

 

[repperl]

Did you see the intake valve bump open when you watched the valves?

I did see that, which made me think the compression relief was still working. But, was still 1/2 turn and locking down every now and then. Makes me think its working sometimes and not others. Covering the intake to stop compression gets it going enough to were I can release and it cranks fine.

 

[repperl]

Did you see the intake valve bump open when you watched the valves?

I also wonder if the intake valve is sticking open if the compression relief is bad. This would allow fuel back out the intake, correct?

 

[Scrubcadet10]

Backing up a little bit, when did this start? did you use it one week, and then next week it wouldn't start?

 

[repperl]

Backing up a little bit, when did this start? did you use it one week, and then next week it wouldn't start?

It all started when the fuel pump went out (checked and no fuel coming out of pump) replaced it and wouldn't start. Was doing the 1/2 turn and stop deal. Went to adjust the valves and realized it had dumped gas into the oil as well. Did an oil change and read online that the 1/2 turn and stop deal was a sign of bad compression relief valve and found the cover the intake trick, which works and it tries to start, just turns over and over.

 

[repperl]

One of the cam lobes could be wiped out, i.e. the exhaust valve not opening, and the compression blowing back when the intake opens. Just doing simple tests and observing.

If you could take pics or a movie, then we could all see what you see.

https://flic.kr/p/2jZRUin

here is a video of the valves. Looks okay to me, but I’m still new to this. As you can see, fuel mixed with the oil again, I’m going to assume it will need a new carb?

 

[Scrubcadet10]

Oh, it's coming out there? I thought you meant back through the carb.
Drain that oil asap, change the filter if it has one, and rebuild or replace the carb

 

[Fish]

Good thing that you aren't a smoker!!