Jimc218

I need some help,
I purchased this truck a while ago and slowly rebuilt the engine.Machined to 40 over and everything is new except for carb and distributor.I went to fire it off and it want run unless I put a rag over the carb but no missing or backfiring.I’m pretty sure it’s the carb. I rebuilt the carb and have gas in the sight window.All diaphragms have been replaced.4 cans of starting fluid testing for vacuum leaks and none found.I pulled the solenoid and it does click. Question 1: With the solenoid completely out, should I have gas coming out the hole while trying to crank over?I don’t, this may be my problem as I plan to tear into it one more time before I buy a Weber.However, here is my second problem. Double checking everything I noticed the timing was off with the light both vacuums plugged as it was running with the rag over carb but I ran out of adjustment on the distributor.I pulled the number 1, ensured it on compression stroke but the distributor will not line up with the number 1 on the cap, I swore it did when I put it together.I then Doubled checked timing marks and the crank is right at zero and my keyway is straight up and down, The camshaft is about 11:30 position with the dowel at 12:00.Also, I noticed that when I rotate the crank left or right, I can see the timing chain tensioner suck in and out depending on which way I go and the chain seems to loosen on the side with no tension.As I rotate to the right and bring the crank to top dead center I noticed If I rotate back it’s about 5-6 degree difference before the cam actually moves? and the same the other way.Has anyone experienced this?All parts are new: chain, tensioner, gears, and guides.Any help would be appreciated.Thanks in advance.

wyoming9

iTrader: (1)

Who put the engine together??

Are you sure you got the right year parts??



Even though your truck might be a 87 the engine could be older.

Did you buy this truck with the parts in a box?

Did this ever run??

Jimc218

Good day,

I have no history on the truck but it was disassembled when I purchased it. However it is a 1987 engine and all parts were ordered for 1985 and above.

lonfu

I've been working on a similar problem on my 85 4x4 22r pickup carb model, so here are some things to check. first check your harmonic balancer to make sure the timing mark is lined up with the keyway. Big wheel on the bottom. Then set your your timing mark to TDC. Your #1 cylinder should be at the top. Top valve cam keyway should be at 12 oclock, dimple should be at 11:55. Both lobes on #1 should be set about opposing downward 45 degree angles. Both rocker arms for #1 should be loose. Next set your dist to the center of #1 contact just to get it started. Check your dist transducer to make sure in is close enough to the signal rotor and use a ohm meter to make sure it is between 130 ohms and 160 ohms +-5%. I've tested, replaced everything on the smog, mechanical and electrical systems and my timing mark is still at -5 degrees. Noticed a few days ago that the transducer rotor (4 point star) that passes by the transducer is not perpendicular to the dist rotor (plastic removable) rotor "seat". No way to remove or repair the signal rotor that I can see, so I ordered a new distributor. OUCH!!!! I tested the coil, but replaced it anyways. I didn't know how to test the ignitor, so I replaced it to. If any one has an 85 would you check your distributor signal rotor to see what the angle is? a pix would be great.

Inherited this truck from my father in law, he bought it new, I was trying to finish this so I could take him for a ride before he passed. I didn't make it. We're best friends, Yoda enthusiasts and fellow wrenchers....

Besides the timing issue, it starts and runs smoothly when cold, but when it heats up has a bad "flat spot" when the carb is first opened. Yes, I checked the both acel pumps and pulled the "factory rebuilt" carb apart and blew it all out. I've owned Yoda's since 1985, so this is not my first rodeo.

lonfu

I replaced the distributor and was able to correctly set the timing. Much of the flat spot disappeared. I could only figure that it must be a problem with the mechanical advance plate. I replaced the carb with a brand new chinese carb. It works perfectly now, all of the flat spot is gone.

The old carb must have an internal leak.

What is sad is that both the units I replaced had been rebuilt.