29cc DDM

[C-Mac]

Hello,


I recently replaced the stock motor with a 29CC DDM and after break in it seemed worlds apart from the stock motor. I could tell right away the power difference. I was on my second tank and it seemed like the balls were ripped off the motor and I wasn't able to get the pick up or top end out of it that it previously had. Could it be my fuel mixture? Is it just a tunning issue? Is it a crappy motor? Any help would be greatly appreciated.


Thanks again,


C-Mac

 

[kryptonite]

well, it not a crappy motor, that for sure. defects are a thing of the past if thats what you are refering to. first off, pull the plug and let me know what color it is.. we will continue after that..

 

[max 1]

Check And See If Plug Is Tight ,color Like Kryp Sead ,check That The Head Casket I Not Blown Out ,and Check Fore Vacum Leaks .use Wd40 And Spray Around Intake Gaskets ,if There Is Aleak Rpm Will Rase The Idle And U Will No.

 

[C-Mac]

Well looks like the plug is a white NGK cmr 7h and it was loose. I have an oily residue on my carb because it was loose. I R smrt

 

[Sucram]

My vote is on the base gasket has been blown

 

[Sucram]

yeah that would do it

 

[C-Mac]

I'll pull the motor tonight and check for gasket issues

 

[C-Mac]

Took the motor out and seems like there are no gasket leaks just a loose plug. I'll take it out today and see how she runs.

 

[C-Mac]

Ok So I took it out today and it seemed to run fine for about 15 mins before I started noticing power loss. It was like it was getting to much fuel and wouldn't go anywhere but if I let it idle it seemed to burn off and would run great till i gunned it.I didn't notive any leaks anywhere. Could I have blown the motor? Should I try a new spark plug? I am lost and any help would be great.


Thanks,


C-mac

 

[Obeast44]

When its doing that unscrew you gas cap and see if its Vapor locked.

 

[yolonda21]

Vapor locked........

 

[kryptonite]

ya, check to make sure the gas cap is venting and not building pressure. that takes about 15 minutes to happen, then it will run like crap. almost like you sucked a small bird thru the intake..lol.. what i meant buy checking the spark plug color was the felemant at the end. the color of the spark plug (end) will determane how your motor is running. if the end is dark black and oily then you are too rich. if the end is a light chocolate, then its good. if the end is white/grey or chalky then you have a lean condition. a lean condition could be coused by an air leak or a carb adjustment. if the carb is set at the stock setting and you have an upgraded motor/pipe; then it wont run well for long. the carb will get "loaded" up with fuel. you will have low exceloration and stumbling at the top rpm. stock settings are very rich settings for protection..

 

[C-Mac]

I changed the plug and took it out in the front yard and sure as sheet aftere about 5 mins it was doing the same thing. Fine at first then bogging down like she had no power. I will try and check the cap again but other than puttign the vent tube in it I have drilled a larger hole in the cap. There is a plastic cap under the concave rubber cap. Seems like a gromit to stop the fuel from coming out if the truck is upside down which has 3 small holes in it, which I made bigger, then a rubber cap over that which also has a small hole in it which I haven't made bigger. Can the tube length be an issue? The plug seemed clean so I am not sure. I appreciate all the help. Kinda sucks cause I found a wicked jump and now I can't have fun

 

[kryptonite]

we have to get you to that jump with the quickness!! to check if its building pressure just release the cap when it starts running crappy. you "don't" want to hear the air release. the tsnk doesn't need pressure to push fuel into the carb like a nitro. the length of the fuel line coming off the gas cap is not important. mine runs thru the cage and exits at the rear bumper. i removed all the cap inserts and have just the large rubber cap that i cut an "X" in the center. pull the spark plug and see what color the element is. that will tell us right away what the issue is. another silly thing to look at is the clunk inside the tank. i had one from the factory that was only half way into the tank. had to put new fuel line on it to get the tank clunk to the bottom. the line with the clunk goes to the bottom of the carb. the return line goes to the top, next to the primer bulb.. if those are reversed your motor will still run, but run like absolute crap.

 

[DemonRC]

C-Mac check this spark plug color chart and tell us what number you are on:


http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

 

[badboy2]

have u touched the needles?maybe theres a leak on the carb ?

 

[noyb98098]

Just got this engine with the stock carb, had the same problem with power loss today, it ended up being my needle settings. Not saying it's the same for you but after adjusting mine I was up to full speed again. I have to admit it was strange that one day this thing was flying and the next it was bogged down until I change the my carb settings.

 

[C-Mac]

Catchaser it looks liek a 4 or 7. I'll check the clunk when I get home from work and I am sure the needle settings on mine are both out 1 1/4 turns. I'll as well pull the crap out of the cap except for the rubber dome which I will cut and X into. How often do you change the spark plug in these machines anyways?


You all rock and I can't thank you enough for all the help I am getting!!!

 

[DemonRC]

A 4-7 spark plug color would be a rich setting which could be explaining why you would die at idle after a WOT. Try going to 1 1/8 on the L needle. That should pick up your idle some so it won't die at idle and also lean you out a little to get your plug color in the sweet spot.

 

[C-Mac]

Just took the plug out after running it again in the front yard and tuning it a bit and she does the same thing. Took the guts out of the fuel cap except the rubber dome and there was no pressure inside. The spark plug looked like a number 11 or 19 now but still no power. I know the fuel lines are correct as well since I changed them and the glunk is at the bottom. I am stumped now. does this mean it's a motor issue?