LRP Z28R spec 3 problems starting

[Urban Monk]

LRP spec3 with roto start, RD Logics twin stinger exhaust in LST2. Run in to manufactures recommendations!!

Engine has always been very temperamental starting and tuning, will spend ages getting it started and tuned properly, then next time take it out will take ages to start will reset to factory settings and start again?

Took it out today having just stripped the engine down and giving it a polish, piston, piston sleeve, crankshaft!!! Still took a while to start, once started tuned it to perfection constant blue trail of smoke, running at 235 temp, popping wheelies etc etc, went to put body shell on ready for some bashing and the engine just stopped and wouldn’t start?

Checked:
Glow plug took it out checked it would glow GOOD!!!
Glow starter fully charged!!!
Fuel "Blue thunder 25%" no air blocks etc!!"
Engine compression GOOD!!

CAN YOU HELP????

 

[Coach Z]

Sounds like you're checking all the right things. Did it quit idling or when you were on the throttle? Air leaks, carb problem? Post up some more details, there are a ton of folks on here with that mill.

 

[Urban Monk]

Sounds like you're checking all the right things. Did it quit idling or when you were on the throttle? Air leaks, carb problem? Post up some more details, there are a ton of folks on here with that mill.

Hi Coach Z

Engine has only sarted straight away with no agro once or twice before, then thought fantastic cracked it however nxt time took it out back to the drawing board?? as far as the tuneing i've always put the fact it needs doing down to atmospheric temp humidity etc.

This time the engine just stopped idling, checked for air leaks also checked carb took of filter looked inside to check was all working properly, all cool??

Spent nxt half hr trying to get it started then had to stop as batterys whent flat on roto...

 

[neobart]

I recently had some problems with a STS engine. It would just die at idle. No loading up or anything, it just sounded like you put a shoe to the flywheel. I traced the problem to the rear bearing. It was seized which meant the crank was spinning inside the inner race. That was enough for it not to idle right.

Also have you tried the stock LST2 pipe on the spec3, I find it works really well. I've never liked the Rdlogics one.

 

[frickenjoey]

Question yourfuel ....how old is it. Has it had a chance to draw moisture. It is rather damp in England....I lived in Suffolk for several years..Where I am at that is a huge problem and I almost scrapped a mill because of stale fuel. Neobart had a good idea with the one way causing problems. I have a LRP as well but luckily I have had good luck with it. Keep us posted.

 

[neobart]

Not the OWB, this bearing.

 

[SMaxxin]

I see two things in your first post that I would change, and one that is unchangeable.

1. Blue Thunder fuel....I always had trouble tuning with it
2.Dual stinger exhaust...don't like them, more tuning issues
3.You polished everything, nice but it's very easy to slip and mess up ports without even knowing it....more tuning issues.

I would also try a new glow plug, I know you said it's working but I have seen that be the problem even when it seems to be working.

 

[Urban Monk]

Hi Guys

Thanks for your help i shall check that bearing, my brothers and I use the same fuel and he has no problems?

The problem isn't so much the idle as when the engines running i can adjust this it's more the fact that it just wont start, i would of thought if it was a problem with just the idle the car would start but then just cut out when left to idle?

I shall try the losi exhaust if i can remember what i did with it, will let you know how i get on, once again thanks for all your help!!

I see two things in your first post that I would change, and one that is unchangeable.

1. Blue Thunder fuel....I always had trouble tuning with it
2.Dual stinger exhaust...don't like them, more tuning issues
3.You polished everything, nice but it's very easy to slip and mess up ports without even knowing it....more tuning issues.

I would also try a new glow plug, I know you said it's working but I have seen that be the problem even when it seems to be working.

Hi SMaxxin

1. What fuel do you use, the only reason i use the blue thunder is it's supposed to cut the engine out if it gets to hot?
2. Will definately try a new exhaust and check ports!!
3.as well as change glow plugs

Thanx

 

[Timmahh]

never heard of Temp Gauging fuel myself. but i too had issues with blue thunder. I'm using byrons original now without any issues.

you can tell if your front bearing is leaking by the fuel and dirt puddle under the flywheel area. sometimes it leaks very little but should be a small mess under that.

if the flywheel is loose, or just not as tight as it should be, this may cuase a leak.

the exhaust is pretty important. a different exhaust will/can drastically change the way a motor runs/tunes/temps and performs. deffinatly worth a look.

a new plug wont hurt. could be a coil getting bad in it.

break in can also be a pain. specially for those newer to nitro. Keep in mind the H needle feeds all fuel, the low fuel feeds fuel just for the low rpms. when you adjust the H needle it will effect the flow of the low needle.

 

[SMaxxin]

This is just a though....You said it was running at 235 degrees. When I get mine over 230 I can tell it's running lean. I don't know what the climate is like where you are but for me the engine runs great and has tons of power running around 210-215. I'm not sure what engines you are used to tuning but I also noticed that very very small adjustments make a difference. Maybe set everything back to factory setting and start all over, remember depending on climate it is possible that factory setting or not as rich as you would think. Talk your time, after each adjustment run it a while to see if it makes a difference before adjusting the needles again.

Good Luck!

BTW, I'm running Byrons fuel in my LRP

 

[bnrpat09]

get a different pipe it doesn't have enough back pressure to push enough fuel into the motor to keep the idle right!!!

just run a reaular style header and pipe!!!

 

[SuperMaxx83]

i had a customer with a lrp in his lst and he had the same problems and after some checking i found out a few things.
1. had a air leak
2. Low speed needle needed to be adjusted
3. Pipe sucked(some flea bay special)
4 Gas tank had a bad leak under the cap
After i fixed all of this it ran like a dream around 215 to 225. Also he switched to byrons cus thats what i run in my 3 lrps.
Hope this helps you out.
Thanx John