kengentry5000

My Feedback: (2)

My Zen G260 will still not turn over. Items I have looked at and hopefully eliminated as a cause:

- Choke - Definitely in the choke position to try to start it. Only priming with a couple of good squirts.
- Ignition - hold spark plug to cylinder, pull starter and I see sparks jumping across gap. I tried a brand new NGK CMR7H plug also.
- Kill switch - probably goes without saying because I have spark. Today I removed the switch and still had visible sparking. I used a nice voltmeter at work to confirm the switch is completely 'open' when in the out position and completely 'closed' in the 'kill' position. The switch is not sticking at all.
- Fresh fuel - I dumped the Coleman camp fuel in the tank and fuel lines and went back to gasoline and Maxima 927 at a 25:1 ratio.
- Flooding? - I emptied out the cylinder by pulling the starter with the car upside down and let the car sit to evaporate the rest. I also had a dry plug.
- Insulator block/gaskets - I removed the insulator block and inspected it and gaskets around block. All look good. I wiped all the surfaces and reinstalled the block.

Would a bad piston ring cause this problem? There is no sound of metal-on-metal like the ring is scraping the cylinder wall.

Who has replaced a ring here? Can it be done with simple hand tools? Did you use a torque wrench to get the head bolts tightened back down or did you just 'get them tight'? Did you have to replace the gasket between crankcase and head?

I am thinking about removing the head and inspecting. I could post pictures here. Would anyone be willing to look at the pictures to help me diagnosis this?

Has anyone performed a 'leak down' test before to find vacuum leaks on these engines? Is there a 'quick and dirty' way to check for leaks using something like window cleaner?

The summer is getting away from me and I really want to get my gasser fix.

As mentioned in another thread recently...The engine has been starting and running reliably. I have been running in my front yard for 8 - 10 minutes per run lately. On my last good run the engine idle seemed higher than normal at the end of the run. That is why I am thinking bad piston ring or vacuum leak.

Any help is greatly appreciated.

Ken

8000ft

I have done the ring and cylinder twice on mine and it is easy. no special tools required. It does take some time but not to bad, about 1 1/2 hours from start to all back together.

pull the engine out of the truck and go for it, when you get the head off look at the cylinder wall, if it has deep scrapes in it thats probably why it doesn't want to run.

the good news is that a new ring and cylinder is all that you need to get it running again (provided that the bearings are still good which they most likely are).
Also, as long as the piston appears to be in good shape don't bother with buying a new one.

post some pictures and I'm sure we can help.

kengentry5000

My Feedback: (2)

I will get some pictures of the piston, ring and cylinder up ASAP.

Is it possible the piston and cylinder could be okay but the ring be bad?

Ken

radio_controlled_mad

i know u said u had a spark - but sometimes a plug fires outside the engine but doesnt fire in a combustion situation,i had that happen to me twice - messed on changing needle settings ect and it was all solved with a quick plug change,if the ring is worn you will have low compression when u pull the handle

hellya

Do you have the idle screw set on the carb?? no idle no start.....also check to make sure your tunepipe isnt clogged up with oil...if your flooding when trying to start the truck and its never done that before.......... thats a signal to check the tunepipe

kengentry5000

My Feedback: (2)

I will pick up a spark plug gap tool on the way home to check and set the gap on the new NGK CMR7H plug I tried. I didn't check/set the gap before trying it. I will do that before pulling the cylinder off.

Hellya, I had not touched the H, L or idle screws in months leading up to this problem. One of the first things I tried was to reset the H and L screws to factory position to ensure they had not drifted. I didn't tweak the idle screw.

As mentioned above the idle speed of the last good run was higher at the end of the run than normal. The tank was half full so I don't think it was a low-fuel idle problem. Would a vacuum leak or a bad piston ring cause a higher idle?

hellya

If your flooding when trying to start and you have done nothing different to your carb ...clean out your tunepipe[sm=thumbup.gif]

Not saying that is the problem but it might be

radio_controlled_mad

check the cylinder head gasket aint blown out - even the smallest piece missing would suck in air and make the engine idle fast or take 1000 pulls to start

kengentry5000

My Feedback: (2)

I have a stock Firehammer muffler. Is there any cleaning necessary with a regular muffler.

RCM, if it will not start with a new, properly gapped plug I will be pulling the cylinder off for inspection. I will check the gasket at that time. Hopefully will post some detailed pictures as well.

Thanks for all the great suggestions guys. Keep 'em coming!

kengentry5000

My Feedback: (2)

Anybody using a copper head gasket? Is it worth spending $9.50 USD instead of $2.50 USD for the regular gasket?

kengentry5000

My Feedback: (2)

Also, anybody ever have a warped insulator block? How could you tell it was warped? Did you file it flat again or just replace it with a new block?

radio_controlled_mad

i read useing copper head gaskets transfers unwanted heat into the crank case - not sure how much truth is in that? atleast it will never blow out but would imagine to get a good seal with them u would prob need to add abit of liquid gasket also.if your striping the case i would spend $10 on a new piston ring & a gasket set for cylinder head/carb ect

Timmahh

10 or so years ago, that all the head gaskets were ever made from is copper. one use, once you compress the copper its seated. so you needed a new headgasket every time you pulled the head. yes you would get a lil heat transfer, but youd also get a better cooling as more heat was at the head, which at that time was fully exposed. no shrouds. with new technology, came new material. the main cost differance is the differance in copper costs over the other materials being used. i d say go for it. but be sure you have it running first, or you ll be throwing away a used copper headgasket without any runtime if your motor dont start and you pull the head off after useing the copper one.
Timmahh

kengentry5000

My Feedback: (2)

I didn't think about how it would be a compression fit making the gasket a one time use deal.

It sounds like those brass compression fit plumbing parts like used in the water line for a refrigerator ice maker. Try to reuse one of those parts and the fitting will dribble water all over the floor.

Thanks Timmahh. BTW - my wife saw your signature and said, "What the (*&)& are you reading!" It took a moment to explain your nitro addiction

8000ft

I have reused copper gaskets in the past when I couldn't afford to get a new one. What I did was to set the used gasket on the concrete floor and heat it up with a torch, thus expanding the copper to it's original size (or close to it).

Timmahh

yup, thats the oldtimers way of doing it and works pretty good. i have heard of oldtimers doing this for quite a few times on the same copper gasket, but only did it once myself. i just didnt get the performance i wanted. put on a new gasket and things were better. so i only used them as a one shot deal after that.
LOL leave it needing to be explained to a gal..lol no offense if shes reading this part also.> lmao and ducking.
Timmahh

J_D

try a NGK CR8 HSA, might be what ya need.

kengentry5000

My Feedback: (2)

Those Aussie chicks know their RC, that's for sure!

J_D

thats my gf

but yes chage ur spark plug, i had a plug, that HAD a spark, i cleaned ect ect. but it would not start.

EDIT: just noticed u tried a new plug. but try the CR8 plug, its hotter

are u getting the spark at the right time as well?

ScooterTrash

Double check the EPA ( End Point Adjustment ) on the radio for the throttle servo?

radio_controlled_mad

8 is colder - the higher the number the colder the plug

J_D

ok wateva :P

its better, there u go

kengentry5000

My Feedback: (2)

Dave's Motors shipped my G260RC with a Champion RZ7C which I have run for 7 months or so now. It has some deposits on it but not any 'caking' or otherwise really bad stuff. I haven't had any trouble with ignition before.

I had a new NGK CMR7H plug in my toolbox so I threw in to try. I didn't check the gap on the electrode but will as soon as I pick up a gap tool.

Hey Scooter, thanks for the EPA suggestion but I'm pretty sure that is not causing problems right now. I don't even have the radio turned on. I'm just trying to get the engine to start and idle. I will check out the EPA settings once I get past the starting problem.

Ken

J_D

just buy a new engine

part-time

My Feedback: (1)

ken im in the same boat as u. i called a local shop and he told me to try a litlle carb cleaner to get it to start. and if it did not. i should pull the head and make sure the ring is lined up right, and make sure there are no scratches on the wall.