Fresh Rebuild Sluggish under a load

[Miguel Verde]

Hello all.. first some background.. I searched extensively on the forums and got some mixed ideas, but nothing similar to my situation so I thought I would reach out. I am here in Colombia and just had the 1300 rebuilt up to a 1400. It would not pass emissions due to smoking, and I was having problems with it staying in 3rd gear and since I found a fairly low mileage tranny and since the motor needed to be pulled to put the tranny in then I figured why not go all in with the engine. The car was running like a top pre rebuild and the mechanics here work in fairly primitive conditions, as you can see from the pics, so I was a bit skeptical but they came recommended and R4's are common here so they knew what they were about. They got the engine back together, seems solid, no wierd sounds, and I passed the emissions, but the engine is seriously lacking power and it is hesitating during acceleration and feels like it is surging or hiccupping at cruise. Feels like it is always going over little bumps in the road. This was not happening pre-rebuild. I used to do a lot of mechanical work back in the day, but here in Colombia in retirement I have just basic hand tools and they work so cheap its just not worth doing it myself.

New Plugs/wires/distributor cap/rotor
I put electronic ignition on it when i bought it 4 years ago.. has been working great
Carb was not worked on neither was the intake manifold removed from the head
I sucked on the vacuum tube going to the distributor and nothing is moving, this was suggested in a previous post..but why is it a problem all of a sudden and was fine before the rebuild?
Mechanics here are not troubleshooters.. they try to do a job as quick as possible for 10 or 15 USD.

My important questions are if the engine is running well enough to get me around and pass emissions, can I eliminate the possibility that the timing chain is installed one or more teeth off? Also can I eliminate a poor valve adjustment from my list of things I need to delve into? Just trying too eliminate things that are probably ok and would be a major pain to investigate with the tools I have.

I am down to the carb or the vacuum advance as potential problems or the carb as potential problems. Here I cannot buy a rebuild kit for the Solex carb, I must buy all the jets and gaskets as I need piece by piece, its a real pain. As I said I sucked on the vaccum but it does not move one little bit no matter how hard.

I have messed and messed with the timing and the carb adjustments.. to no avail. I have extended all my abilities now I need some advise to continue. Parts are cheap but I need to go into the city for them and its 2 hours in a bus.



If anyone is curious about the cost of parts and labor here I would be happy to share.

 

[angel]

The answer is almost certainly on the second photo: Hose from inlet manifold goes directly to the carburettor float bowl. Remove the carburettor end, plug it and test drive the car to check if it runs better.
Check valve clearances with engine cold: inlet 0,15mm, exhaust 0,20mm. You can quickly check camshaft timing as follows: Bring No1 cylinder to TDC on firing stroke and set valve clearances so that you just eliminate rocker arm free play (0 mm clearance.). Rotate crankshaft one full turn to TDC, this time no. 1 cylinder will be on overlap. At this point, loosen both rocker arm adjusters so that you have 0 mm (or minimal - say 0,05mm) rocker arm clearance. Turn crankshaft one full turn once again and measure both (now very wide) rocker arm clearances - they should be equal to within 0,20mm.

 

[Miguel Verde]

PS double checked that the vaccum advance seems completely inoperative.. not sure if it was disabled for the electronic ignition or not..

 

[Miguel Verde]

The answer is almost certainly on the second photo: Hose from inlet manifold goes directly to the carburettor float bowl. Remove the carburettor end, plug it and test drive the car to check if it runs better.
Check valve clearances with engine cold: inlet 0,15mm, exhaust 0,20mm. You can quickly check camshaft timing as follows: Bring No1 cylinder to TDC on firing stroke and set valve clearances so that you just eliminate rocker arm free play (0 mm clearance.). Rotate crankshaft one full turn to TDC, this time no. 1 cylinder will be on overlap. At this point, loosen both rocker arm adjusters so that you have 0 mm (or minimal - say 0,05mm) rocker arm clearance. Turn crankshaft one full turn once again and measure both (now very wide) rocker arm clearances - they should be equal to within 0,20mm.

These hoses weren't changed during the rebuild.. no attention was paid to the carb just put back together as it was. But I will certainly try. the other side of that rubber fitting attached to the top of the float bowl goes to the top of the rocker box cover.

 

[Andy McGhee]

It's difficult to be sure from the photo, but it looks as though the inked manifold nut might be missing (forgive me for copying your photo!):

 

[Miguel Verde]

It's difficult to be sure from the photo, but it looks as though the inked manifold nut might be missing (forgive me for copying your photo!):
View attachment 28047

definitely is! Will attend to that pronto thank you! but doubt that is the major problem...