serging ez-go

[pistolpete]

has anyone had a problem with a robin engine serging? even at quarter throdle? what to do to fix it? i've spoke with tom- the guy who designed the robin engine and he's even stumped.

[gaminde]

vacuum leak or float level too low is it lacking power also.

[pistolpete]

yes it does, cant get it to go past quarter throddle. i've had this piece of s*** for 3 1/2 weeks now. rerung it, new rockers,cam,coil,pulse coil, fuel pump,3 carbs (2of wich are new), new intake valves & lapped all valves in with new stem seals, been over timing & valves 100 times. pulled motor back out 3 times and tore it back down lookin for sumthin outta the norm. i've even talked with tommy in georgia, (the guy that designed that motor- real nice and helpfull to) and he asked me a butload of questions. guess i answered everything rite cuz he is also stumped. its gotta be sumthin stupid. usually is. i'll try to put sum permatex on intake gaskets. i'll try anything at this point. i'm lookin like a real dumbass to my customer.

[Michael Eddie]

Here are my findings when I was in a similar situation. These engines are touchy, especially after you adjust the valves. Before you continue reading, it gets expensive. The carburetor may need to be replaced, OEM of course since the aftermarkets are not worth anything but a headache. Replace all intake gaskets for new, replace the fuel lines, spark plugs, replace the fuel filter, replace the fuel pump if needed. The valves need to be adjusted perfectly.

[Michael Eddie]

yes it does, cant get it to go past quarter throddle. i've had this piece of s*** for 3 1/2 weeks now. rerung it, new rockers,cam,coil,pulse coil, fuel pump,3 carbs (2of wich are new), new intake valves & lapped all valves in with new stem seals, been over timing & valves 100 times. pulled motor back out 3 times and tore it back down lookin for sumthin outta the norm. i've even talked with tommy in georgia, (the guy that designed that motor- real nice and helpfull to) and he asked me a butload of questions. guess i answered everything rite cuz he is also stumped. its gotta be sumthin stupid. usually is. i'll try to put sum permatex on intake gaskets. i'll try anything at this point. i'm lookin like a real dumbass to my customer.

Did you reseat the valves? If you spray starting fluid down the intake will it run faster?

[blake80]

I agree with Mattie. Every problem I had with mine was due to the valves. I spent a weekend out of town with mine running like crap. me and a few motorcycle mechanics kept looking at the carb because it ran like it wasn't getting fuel. After I got home I racked my brain for a week trying everything. Decided to check the valves again, I had one out of adjustment.

[pistolpete]

the whole entire fuel system is new, including pump. tryed aftermarket carb, no prevail & heard what matti said bout them so i took one off another ez go thats running fine. no help. been over the valves boo-koo times. got home last nite and sealed the intake gaskets with a skim coat of permatex both sides. no help. havn't tryed starting fluid, but did carb cleaner from a drip to half spray. still didnt change, would just fall on its face. tryed with air line adding air. no help. pulled thye motor back out last nite, tore it down. found nuthing outta the norm. i'm starting from scratch AGAIN. got new rings and gaskets on order. try this again friday. thanks for the input guys.

[blake80]

Have you done a compression test on it?

[pistolpete]

5 times. 125-130 consistantly.

[gaminde]

What happens when you choke it, what do the plugs look like, black smoke does it start right up ????

[pistolpete]

have to choke it breifly to get it to start, cranks rite up no problem. little bit of black smoke while running. run it at 1/4 throdle for 2-3 min & pull plugs they are black with soot( to much gas) . pulled short plug wire, dont want to run, put that one back on & pull the other it will barely run. recon i'm just gonna start over from scratch. gettin .25 over rings & file till i get my gap of .08 like last time. got new head gasket commin to.

[gaminde]

Plugs black to me would mean

1 weak spark
2 valve adjustment
3 timing
4 carburetor

really does not sound like internal engine problem unless its some sort of timing issue.

[pistolpete]

got blue spark that will jump over 3/8ths in. been over the valves 100 times. settin em all at .04 . had that timin belt dead on, tooth forward and back, still runs the same. have the carb that came on it, a new aftermarket one, and a new oem that i took off another cart thats running fine- yes ez-go cart. keep thinkin! i need all the help i can get.

[gaminde]

Im thinking spark it will run on one cylinder and not the other so one cylinder is not pulling it weight. are both plugs the same darkness, compression is real close on both.

Ok we know were not getting good burn could the valve lift be off could it be .06 instead, what engine is this again and was there any head work valve re-seating, are we still getting popping through the carb.

[gaminde]

got blue spark that will jump over 3/8ths in. been over the valves 100 times. settin em all at .04 . had that timin belt dead on, tooth forward and back, still runs the same. have the carb that came on it, a new aftermarket one, and a new oem that i took off another cart thats running fine- yes ez-go cart. keep thinkin! i need all the help i can get.

Well should valve setting be .004 !!!!

[gaminde]

another way to check your adjustment is lightly seat the valve and back off 1/4 turn maybe while your there check it both ways and see how close it comes out.

[pistolpete]

however you write it i set the valves at 4 thousants. yes both plugs look the same. same amount of soot on both. compression is the same on both cyls. it is a robin 35C. i replaced both intake valves cuz they were sucked into the head, lapped all 4, and performed a leakdown test on all of em when i did it the first time, checked em again last nite & they are not leaking. i do get poping thru carb if you go over quarter throdle.

[pistolpete]

i will do that when i put the new rings in it friday , wont get parts till then. got head gasket commin to since i had this one off twice. this P.O.S is kickin my but. i do this stuff for a living. NEVER had this much trouble outta sumthin this small. built many a motors in my time.

[gaminde]

would it hurt anything to set it at .006 and test it really sounds like the intake is not closing at the correct time would seating the valve change the geometry any, as far as opening ??
if its popping through the carb some timing is off ??

are both valve springs the same could they have been swapped and intake should be stronger

what was engine doing when it was first brought in.

[gaminde]

valves should be 12mm= .0047 which is closer to .005 and not snug just touching gauge and have good back and forth movement.

[pistolpete]

in the book they dont show any differance in the springs. i agree ithat the valve is still open a touch when it fires. causing backfires. my customer says it "ran fine" just smoked and used oil. i just wish i could tell him he full of s***! but this is the guy that i turkey hunt on his property sooo. the intake valves were sucked in the head, rockers were washboarded & cam wiped out. i went to my local ez-go dealer and pulled good rockers & cam outta a motor they had to save $600.00 no damage done to them, they are in great shape.

[pistolpete]

yea the book says between .004-.006 so 5 would be the target i guess.

[pistolpete]

fixin to leave work, be back in the am. dont have internet at the house.

[gaminde]

valve specs per manual
12 to 15 mm = .0047 to .0059 in
this is tight so if you were setting it snug at .004 its too tight.

[blake80]

now i remember why i got rid of my 350 and went to briggs.

[Michael Eddie]

another way to check your adjustment is lightly seat the valve and back off 1/4 turn maybe while your there check it both ways and see how close it comes out.

I do this to all my EZGO's. Depending on how beat up the inside of this motor looked, i might have replaced the cylinder head as well if the seats looked bad enough.

[pistolpete]

the seats were fine , the motor looks fine internally. no damage. just the actual valves , and the cam & rockers was the only thing wiped out. got all that replaced and the valves lapped rite in.

[gaminde]

pistolpete

Been thinking about this and would like to see you go with a firm .006 then compare the difference between the way it ran and the way it runs at .006.
You can always go .005 later but I would like to see a bigger difference to start this would tell us were on the right track or not.

also .005 is 25% more gap and .006 is 50% more gap thats a lot of difference!!!

[pistolpete]

works for me. i'll get my parts on my way home & build it tonite & get it stuffed. i hope and pray to the robin gods this thing will do rite. a month is wayyyy to long for a motor rebuild job.

[pistolpete]

finally done

ok guys, have no idea what i did BUT i finally got my ez-go turd done. re-rung it, set the valves at.006 stuffed it in, hit the gas pedal without the carb linkage hooked up, hit the throdle and it reved !!!!!!!. tuned it out , drove it up and down my half mile driveway. then loaded it up on trailer and delivered it. sa-la-vi!! will never take in another ez-go gas again. thanks for all the input guys ! pistol

[gaminde]

You have to work on ezgo gas carts, you are the go to guy here, the expert !!!
you have experience now your seasoned

Sometimes you do everything right and it's wrong

Glad it's gone how did you sleep the last couple days

[pistolpete]

like a rock!!! if ya want i'll give ya my cell #. you can call anytime you have a yamaha or club car problem. those are a walk in da park for me. do plenty of harleys too. carts and bikes!! again thanks for the help. i set the valves at .006 to start with, after it ran and reved i set them back to .004 & it ran good. pistol

[Michael Eddie]

Great job! I see your preferred brand is Yamaha now!!!

[pistolpete]

yamaha is my prefered brand, then club car. those to me are a walk in the park, gas and electric.