zen engine pulsing

[sickboy]

Hi all well thought i would get me fs ready for the snow but as i was tuning the engine on the stand at full throttle it seamed to pulse any ideas could it be im getting some air in some where oh i should mention that the returning fuel pipe back to the tank shoot out of the carb while i was tuning it put that back in its right full place then it still was pulsing mmmmm :helpsmilie:

 

[sickboy]

is there anybody that is willing to help

 

[98navi0314]

Return line should not pop off easy.... Trim of a little for a tighter fit.
Also check for air leaks around carb and manifold.

 

[sickboy]

ye the return pipe it didnt pop off it jumped out of the carb you no the plastic part that's where the fuel line goes over but the only thing is the one i have is metal
ill have to check for leaks morrow thanks
still think its strange when i give it full throttle and pulsing like it dose

 

[pipeous]

maybe thre pump is wearing and struggling to keep up under full load? an air leak would tend to show a problem over the full spektrum I would think. or maybe a bad plug wire. I would check it with an ohm meter to see if there is resistance. I had a carbon wire on my 1:1 car the inside had worn and the spark had to jump across the break. it started small so never really noticed it until it got worse...when I finally figured it out the spark was jumping inside almost an inch... each spark made the distance a little further from the arch

 

[voo2doo]

Sickboy ,you have a poop carb mate.I think if its what you describe ,its a CZ , a bad copy but don't quote me.If your having a line pop then you might have back pressure from the crankcase(TOO MUCH) I would strip the inlet and pull the filter out of the carb.re-seal it with new gaskets(or gasket paste) and blow the carb filter out( the one inside) If the mill is pulsing then I would put it down to a blown gasket,because your sucking air.Might be time to re-gasket it.
J.

 

[sickboy]

Thanks lads im going to strip it down morrow its not a copy this i know.
Its the walbro 813 from pit stop but you could be right its might of sean better days ill just juts take it apart then take the carb of my other gasser for now and wait to see what Santa brings for me this year

 

[voo2doo]

Thanks lads im going to strip it down morrow its not a copy this i know.
Its the walbro 813 from pit stop but you could be right its might of sean better days ill just juts take it apart then take the carb of my other gasser for now and wait to see what Santa brings for me this year

New gasket set mate,and then see what happens.
J.

 

[slawhammer]

when you first buy the walbro813 carb..if you don't silacone the hloe on the back
side.upper right corner..it will suck in grit..dirt..that is where the ball is located for the accel pump....your 813 carb is junk..replace it...no need to try to rebuild it..
it will cost you more than a new carb....My opinion here..Slawhammer

 

[zouz10]

I think it's what Pipeous said. The plug wires might be goners.

How is the performance when you accelerate?


Chris

 

[Timmahh]

check for loose plug, exhaust pipe, cylinderbolts and carb bolts. usually pulsing (fluxuation in rpm while throtle is stationary) is a sing of air getting in.

 

[sickboy]

so striped the carb down today replaced the 2 gaskets and for extra i used the silicon seal just to be on the safe side cranked the engine and all well till i give it full throttle and yep still the same problem till my mate was looking at the primer and he said is that right all those little air bubbles in the fule primer mmm i thought no but just to be sure tightened up the 4 screws that hold the primer in place and tryed that and yes found the problem they were loose not to loose but just enough for a leak so now im a happy fellow again

once again thanks for the help lads

 

[sickboy]

Hi all well the problem came back so i thought it would be the same thing nope thats not wat it was so tryed the plug and still a no go then thought screw this ill replace the god dam thing and hey presto problem solved
so i decided to take the old carb apart bloody hell it was full off crap so now ive cleaned it out now will try it to see if that helped any if not then the thing is going in the bin

 

[voo2doo]

Hi all well the problem came back so i thought it would be the same thing nope thats not wat it was so tryed the plug and still a no go then thought screw this ill replace the god dam thing and hey presto problem solved
so i decided to take the old carb apart bloody hell it was full off crap so now ive cleaned it out now will try it to see if that helped any if not then the thing is going in the bin

So it was the carb then?
J.

 

[sickboy]

ye the dam thing works ok normal throttle but when i want to tune it at full revs then it pulses on me.so like i said swapped it around with my other Gasser and problem solved going to test the knackered one morrow

 

[voo2doo]

Thought so,when I was on the spanners we had a Ford Mondeo in and it was blowing lines everywhere.When you put your foot down it wouldnt go over 2500 RPM without it blowing,in the end I took the exhaust off because there was so much back pressure and the cataliser had collapsed,thats where the pressure was coming from.New Cat and it ran sweet.
Yours is probably a blocked fuel return or punctured diafram.
Good luck with the rebuild.
J.

 

[slawhammer]

sounds like a bad base gasket...you could also suck in air from the oil seals
I know this can happen on the clutch side......
you got a air leak some place...possiable warpped intake..if it is non alloy...
or maybe the carb is just worn out....Slawhammer