Engine will not rev

Post by **Rennie** » 19 Jul 2009, 14:27

can some body advise what is wrong with my 2.0l ,air cooled 1981 T25.
I can start the engine but it will not Rev, we suspected fuel stavation , so i striped down the fuel pump and it is functioning OK, we have also striped and cleaned the carbs,checked for Air leaks with carb cleaner, replaced plugs, leads distributer cap and rotar. Before i go for the expensive option of replacing the carbs, is there any thing i have missed that can cause this problem.

Post by **windysurfer** » 19 Jul 2009, 14:45

Fuel filter?

Post by **Rennie** » 19 Jul 2009, 14:50

Yep replaced that, also striped and cleaned fuel tank and replaced all fuel lines.

Post by **dugcati** » 19 Jul 2009, 14:56

I presume you have ruled out electrical issues... the only other thing I can think of could be air not getting into the tack to replace the pumped out petrol?.. a very long shot but if you have ruled everything else out it's worth taking the filler cap off and trying the engine - 10 secs to do and will easily rule it out

Post by **armyphil** » 19 Jul 2009, 15:08

ducati is right on that one i had a land rover do it in the end it sucked the tank up. try running it without the filler cap on and check all breathers?

Post by **Rennie** » 19 Jul 2009, 15:37

Taken fuel cap off but still the same, but what we have noticed is, when you start the engine it will rev up for a second and if i hold the throttle down and turn the ignition on and off it will rev up each time, could this be electrical and what part of the electrics should i be checking ???

Post by **Rozzo** » 19 Jul 2009, 16:20

are you certain its getting fuel? and do you have power to the little solenoids on each carb?

Post by **kevtherev** » 19 Jul 2009, 16:41

Advance unit working OK?
transfer jet working?

Post by **dugcati** » 19 Jul 2009, 18:06

try swapping out the coil and double checking the fuel shut off solenoid/s are working OK/have power to them

Post by **Rennie** » 20 Jul 2009, 18:23

Thanks for the feedback, i have just tested the carb solenoids and they have Voltage to them, and when i take the leads of and on you can hear them click in and out, so i assume they are OK. I have also checked the coil and it seems Ok.
I am thinking of changing the carbs for the single carb ,twin chocke weber conversion, has anybody done this, as i have been told that it reduces the power. If we are only talking of a small reduction in power then i may opt for it as i am looking for a more reliable motor that would be easyer to set up and keep in tune.

Post by **dugwiththevwbug** » 20 Jul 2009, 20:18

sorry if this is really dumbass but i had this when my throttle cable snapped in the middle on a beetle. get someone on the throttle and check on the carb............

Post by **jason k** » 20 Jul 2009, 21:12

Rennie wrote:Thanks for the feedback, i have just tested the carb solenoids and they have Voltage to them, and when i take the leads of and on you can hear them click in and out, so i assume they are OK. I have also checked the coil and it seems Ok.
I am thinking of changing the carbs for the single carb ,twin chocke weber conversion, has anybody done this, as i have been told that it reduces the power. If we are only talking of a small reduction in power then i may opt for it as i am looking for a more reliable motor that would be easyer to set up and keep in tune.

nooooooooo the single central weber is pap!!

the inlet tract is waaaay to long so icinig is a problem as is fuel falling out of suspension.

i doubt yours is a carb problem, it sounds more electrical

if you must change the carbs, dellortos are the only way forward

Post by **toomanytoys** » 21 Jul 2009, 12:25

As suggested are you actually getting full throttle on the carbs.....

Also.. is there a black box on the left of the engine bay with 2 round connectors on it? if so unplug from the box and plug them together..

Is dizzy working correctly? what rotor arm have you got? sometimes the rev limiter rotor arms go weak and they cut out.... fit a std beetle one...

Post by **Rennie** » 23 Jul 2009, 06:57

Toomanytoys you are spot on

Thanks for replying to my problem "Engine will not rev" you were spot on with the little black box i joined the two connectors together and hey presto she will rev again.
I assume the Idle stabaliser unit is the faulty part can you confirm this, or is it a test to prove another part is fuaulty.

Cheers mate

Rennie

Post by **ermie571** » 23 Jul 2009, 07:02

Rennie,

you can run quite happily without the idle stabilisation unit......mine did until the van became beyond economic repair.....

Em
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