4 isn't firing

[Dave Daniels]

Good idea! Thanks.

schnowz <schnowz at localnet.com> wrote:  Sounds right - Easy enough to check. Put a clear piece of tubing on the bowl drain and form a U against the carb and open the drain. Level should be close to the joint IIRC (compare it to No 1)
----- Original Message ----- 
From: Dave Daniels 
To: schnowz ; gpzlist at micapeak.com 
Sent: Tuesday, August 05, 2008 8:41 PM
Subject: Re: 4 isn't firing


I tried switching the wires between 1 & 4, as well as switching the plugs. When I pulled no. 4 plug, it was wet. Also, I looked down the well and you could see the top of the piston was wet. After switching the wires and plugs, the problem remained at no. 4. So, I'm thinking Dave Beard is probably right in that maybe a piece of grip got in the carb and is holding the float open causing no. 4 carb to flood the cylinder while it's running. By the way, I haven't put a fuel filter on yet. Doh!

schnowz wrote: 
Dave
That would also be the case (2 cylinders not firing) for the wire if it 
was a bad connection eg green snot at the end of the wires where the copper 
wire used to be, because the 1 and 4 are in series. The only way it would be 
one cylinder, would be if it was a bad connection and also shorting to 
ground somewhere (bad insulation etc). You can also ohm out the leads and 
caps - the resistance is in the book IIRC. Though this will only test 
resistance of the wire/caps and won't necessarily tell you if you are 
getting high voltage leakage on the insulation. Only way to do that is swap 
the wires with a known good one and the cool header should move with the bad 
wire.
If it's doing it only at small throttle openings I would also suspect the 
pilot circuit - carefully take out the pilot screw after putting a towel 
over the engine. Make sure you get the o ring out too. Squirt some carb 
cleaner in there and then follow with compressed air. You can get the screw 
out by placing a short screwdriver bit in a socket and turn the socket with 
your fingers (not a rachet - which is too big) Before taking it out screw 
it in carefully and count the turns to bottom out - when reinstalling - turn 
it to the same position as before.
By the way a infrared thermometer fired at the exhaust headers are great 
for checkin which cylinders aren't firing.

Pete Staniforth


> Start with coil, plug wire or faulty spark plug, although if it was the 
> coil
> you'd probably see two cylinders not firing.
>
> Bill in Yardley, PA
> wkdenton at verizon.net
>
> ----- Original Message ----- 
> From: "Dave Daniels" 
>>
>> So, it seems no. 4 isn't firing. Any ideas?
>>
>> Thanks,
>> Dave D.
>
>