serious engine probs :(

hi all , well ive rebuilt the engine today with a +2 stuffed crank ,new seals,new piston ring,new steel gaskets,and its still shafted lol , its blowing fuel/air out the carb and sucking through the exhaust , the piston mark is facing towards the exhaust port and the ring is sat right , compression is exellent,fuel lines on the right way ,spark is great but nothing , the airfilter is wet through with petrol so took that off to see what was going on and its spitting fuel out when i pull the pull start , so god knows whats up with it , its not flooded either

thanks for your help


jay

Not sure on that one matey, on a normal engine that would I think be a timing problem but no idea on these, could it be you have scored the ring (very easy to do when installing a head) and therefore its not firing and flooding?

thats the thing though wol its not flooding and its sparking great , i thought it could be a timing problem but i can't see how the timing can change because of the where the woodruff key is and the way the flywheel goes onto it , it should always be the same timing , i just can't for the life of me what is happening lol

I know its patronising but are you deadly sure the piston is on the right way round, I can only think its that

yeah the mark towards the exhaust port , the split towards the carb

Bloody hell you don't have much luck bud

sounds to me like your carb may well be up the spout

Like the diaphragm is getting the fuel from the lines, but then not sending it to the engine

this could be something as easy as a blocked jet
which I highly suspect

You can get replacement carb jet kits, but I would suggest giving another carb a go, before you even think of spending any more money

Timing wise, other than spark gap you can't get it out
There are adjustable coil covers, that alter the timing, an you can get differing profile woodruff keys, both of which I know you've not got, so they, an the timing can be ruled out as a problem

As Wol has said, an I know its a daft seeming thing, but having also done it myself when building engines
Did you get the piston round the right way?

You can easy check if you have, remove the carb, look through the Inlet window, an rotate the crank, if its the right way, you will see the piston ring gap come to the front of the in the Inlet window

if all is good, an I suspect it will be

Then it just screams Carb problems to me

It does sound like carb for the fuel, but that wouldn't explain the suck puff reversal would it?

It only takes quickly chating to someone and the bugger goes on backward lol

yeah the piston is in the right way , the spot is facing the exhaust port and the ring split (twss block) is facing the carb

the air comes out the inlet port even when there is no carb on and the exhaust port sucks slightly , now the carb isn't on so it can'#t be a carb prob in that respect and there is more than enough fuel comming out the carb , its all getting blown out into the filter

WOL wrote:

It does sound like carb for the fuel, but that wouldn't explain the suck puff reversal would it?

It only takes quickly chating to someone and the bugger goes on backward lol

But its Not feeding the engine
So it has to force it somewhere

the reverse puff, is just the normal created pressure being fed back

I highly doubt its actually sucking an blowing in reverse
Just seems that way, as instead of blowing the fuel into the engine as it should be
Due to the blocked Jets, its being forced out the only way it can find

In this case, most likely the choke lever shaft

Strip the carb top off, there is a very small filter in there, an also a breather hole at the side of the white plastic, that can sometimes get blocked with dust an crap, as can the upper filter under the diaphragm

All worth a check

Have you got the right gasket thickness on for the +2 stroke?

ive got a steel rienforced gasket set , the squish seems fine , no slap or anything , it was doing this with the old normal crank in too but not as bad , thats why i bought all this to see if it was the old setup plus the crank was going rusty lol

Well if it was already doing it and you have replace all that then its has to be the carb lol

Have you got another Carb you can try Jay ?

but it does it without the carb and exhaust on so thats ruled the carb out really lol

No mate

Think That's just normal back pressure

Normally that would cause the fuel to feed the engine an so forth

no the other carb is fubar'd i think lol , its fueling fine but its all getting blown out the carb rather than sucke into the cylinder , its sprays out the carb its blowing that strong lol

Perhaps the head has been machined wrongly? It's hard to say..

Anyhows, I've posted your question here:

http://team5hite.forumup.com/viewtopic.php?p=36075&mforum=team5hite#36075

Ian Oddie (http://team5hite.forumup.com/profile.php?mode=viewprofile&u=127&mforum=team5hite), UK champ (on and off road) is a engine guru that frequents the forum.

Another guru TMR Performance (http://www.5thscaleracingforum.com/vb/member.php/1915-TMRperformance) is another person to try.

thankyou mud mate , i will keep an eye on it lol , its really doing me head in now , had another few hours on it again today completly stripped and rebuilt the engine and carb and its still the same , even treid 2 head gaskets lol and nope that didn't work either lmao

Welcome buddy.

Sounds mad, but so is this problem...but have you tried flipping the head around? Or does that not fit?

It is frustrating as hell man...bad ju ju.

yeah tried everything mud :( it does the same thing whatever lol , its not a new head its the one ive always had and it started to do it with the old crank in hence replacing its guts but noooooooooooooo its still does it well even worse tbh lol

Errrr..really strange man..

Have you tried swearing at it?

yeah also tried kicking, stabbing and a poo stick but nothing seems to work

Trying to visualise it, but it's tough, as engine strip down isn't done that often. Changing the ring, and that's only done every 25 litres or so.

its had about 10 strip clean and rebuilds this past 2 days lol all done buy the book to so nothing internally is out of place or in wrong

mixmasterjay wrote:

its had about 10 strip clean and rebuilds this past 2 days lol all done buy the book to so nothing internally is out of place or in wrong

I can see the problem right there Jay.....

You're cleaning it too much, lol.

Man Love hasn't run since last T-Party, but I bet if I put a tank of fuel in it, it would fire up and run perfectly