Smoking and spitting

[stevedjarrell]

Ok, I decided to start a new thread as this has evolved beyond a simple car question. SO Cliff notes, I replaced my engine with a rebuild. 2000 TXT with the 295cc Robin engine. I installed the engine, New Cab, New Plugs. Checked timing and valve clearance (.004). New ground Straps. Cold it takes a little to get started but once it warms up I get white/grey smoke really bad for a bout 30 seconds then it smokes but is slight. I also get a spit back out the carb on deceleration and acceleration, the Cart is on a 6" lift. I put exactly 1.5qts of Royal purple 10w30 in it. Also I have two carbs and did try swapping them. This made no change. So I went thru and re-gap'd the plugs, checked and set the valves again, checked the timing and it was dead on. I also changed all the fuel lines, they were slightly bigger but not by much may be a 1/16th. Trying to think if anything else changed. Anyway I am beating my head against the wall. I have adjusted linkages until the cows come home. Nothing removes the carb backfire 100% and this smoke seems to be worse than when I first fired it up. Both cylinders have 160lb compression. I checked and I get spark on both plugs, although it was not that bright. Any Ideas would be great.

Also it will drive and pull just fine.

[Spicyunicorn]

How much run time do you have on it?

[stevedjarrell]

Since install, Maybe 15mins total over the last week. I am going to drain all the oil out and check it for gas / put in new. I know it was drained before it was shipped to me but maybe not completely? Figure it is cheap enough to do it again to ensure it is not over filled.

[Spicyunicorn]

Agreed with the change of oil last time I rebuilt a Robin I over oiled everything on assembly and it took at least 20 ish minutes of hard running to clear all the smoke if the oil change doesn't smell of gas and a couple long pulls of wide open throttle doesn't clear the smoke i would be in contact with the rebuild company..... Not saying this is the case but some of the companies that rebuild motors get cores in and "rebuild them" by fixing what's is broke and that's it and leaving everything else so it's a possibility they sent out a motor with original problem fixed but maybe a bad oil ring that's how they make profit on these motors

[stevedjarrell]

OK, SO with exactly 46oz of oil it does not smoke at all. Right no I have been slowly adjusting the vertical linkage to the carb 1/2 turn on one end at a time. I have it almost there. No smoke and only a little spitting in the middle of the RPM range. Basically now it spits a few times when going the speed I would mostly use in the campground. So since I am getting a little blow back thru the carb and everything else is looking good I am going to go check the intake valve clearance again. Man this has been a learning experience.

[Spicyunicorn]

Ok with no smoke i would say it's not a internal issue I know you have said you checked valve timing exactly how did you go about it? Even being one cog off can cause issues

[stevedjarrell]

After removing the timing cover I removed the belt, aligned the cam shaft with the notch in the rear plate and then aligned the key shaft on the crank to the mark on the rear plate. Both straight up. Installed the belt, then set the tension and tightens it. I then rotated the crank 2 full rotations and both were still aligned. I then added the plate to the crank pulley and torqued it down. Basically followed the manual for it. I was originally curious it if was off one tooth but it was not. As far as I can tell it is in time. just bizarre, Starts and runs low and high RPMs fine with no spits.

[Spicyunicorn]

Sounds like you got timing nailed down and valves set I'm running out of ideas

[Gearhead1956]

Make sure your air box is sealed and no cracks. Don't know why but it makes a difference. I know with my 295 if I run it with the air cleaner box open it will pop back thru the carb.

Have you contacted the rebuilder?
Did they build you engine or exchange?
Did they replace all parts, rods, pistons, rings, valves ??

I rebuilt mine myself and I had 180lbs compression.
I noticed on mine some wear on the cam and the rocker arms, I guess most are like that. With that wear I had to adj and run and readjust valves several time before it would stay running correctly.

You tried 2 different carbs, have you taken one apart, soaked overnight in cleaner and blow out with compressed air? I had to do that to mine twice with a new carb and found a very tiny piece of milling residue in the passage for the main jet.

[stevedjarrell]

I have not contacted the builder, but I will. I did get it goign this morning and I removed the idle screw completely and re-adjusted the Linkage so it closes completely. Appears to have corrected the issue. I am gong to test it some more this evening. I am hoping that was finally it. However, this was an exchange and not my motor ans since the timing belt is not new I am wondering what on it was actually rebuilt, I would have thought valves, valve guides, rings and bearings? Plus anything that was actually broken?