No start after intake and carb swap. Stumped

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remytherat

remytherat

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I recently put a 340 intake and thermoquad on my 318. Got it all put together and it wouldn't start. Eventually after some time of cranking I got it to fire momentarily. Ran extremely rough before dying a few seconds later.

I did have to take the distributor out to loosen the intake bolt covered by the throttle bracket, but it is back in the right way (I verified) and I checked the timing while cranking (5˚BTDC)

Carb is full of fuel, accelerator pump is working.

Any ideas?
 
Pass side float sticking [ closed ]? Acc pump gets it's fuel from drivers side fuel bowl, so pump shot only tells you that that side has fuel. Rap the carb top with a small hammer where the n/seats are to loosen them.

Also look for fuel dribbling from pri boosters. Could be flooding, o ring problem [ missing ]. Etc
If still no go, remove carb top to check for binding/float rubbing. Congrats on the TQ, good move!
 
Was the TQ rebuilt? The o rings are often omitted by mistake & you get a very rich idle.
If the carb has sat unused for a long time, the o rings will go hard...& leak.

Get some new, fuel resistant o rings 3/8" or 7/16" OD, 1/16" wall thickness & fit them if the above criteria fits. You do NOT need the special Carter o rings. If you are careful with disassembly, you will NOT need new gaskets.
 
remytherat said:
You mean a screwdriver?
Click to expand...


4spdragtop said:
Yes, but no. 2 wires and a momentary button will achieve same result as a screwdriver but you're more "mobile". Screwdriver limits your movement.
Click to expand...


I locked up a starter once by doing the screwdriver and accidentally double hitting it...

Your safer using a remote starter...

Unless you would rather risk buying a new starter....
 
remytherat said:
I recently put a 340 intake and thermoquad on my 318. Got it all put together and it wouldn't start. Eventually after some time of cranking I got it to fire momentarily. Ran extremely rough before dying a few seconds later.

I did have to take the distributor out to loosen the intake bolt covered by the throttle bracket, but it is back in the right way (I verified) and I checked the timing while cranking (5˚BTDC)

Carb is full of fuel, accelerator pump is working.

Any ideas?
Click to expand...


Did the intake seal properly??? Vacuum leaks around the ports???
 
remytherat said:
You mean a screwdriver
Click to expand...
Bad idea, it burns the threaded posts leading to issues later.

A remote switch replicates the key for the starter. Key in run position, adding a wire from the batt pos to the coil side of the ballast resister is helpfully (gives full bat voltage to coil during cranking, don't leave it on after start, or you will burn out the coil)

So what could happen during an intake swap...

  1. Electrical wires could become disconnected / damaged
  2. Fuel lines can become clogged (inside of rubber lines falling apart)
  3. Dist not installed correctly,( I know you checked but best to check at TDC etc.)
  4. Assuming you pulled the plug wires they might not have gotten back correctly.
  5. There could be a vacuum leak


Theses are the places I would concentrate on
 
Screwdriver comment was sarcastic

Pretty sure ignition system is working. Rotor points to. #1 at tdc. wires are in correct order. plenty of spark

Pulled off the top of the carb. both bowls are filled with fuel. i believe the o rings are in place. Carb was rebuilt by previous owner i think but never ran

ED90498F-0603-4A0C-98A6-2341E59BD3D5.jpeg


How and where are possibilities for vacuum leaks? This would have to be a huge one…
Vacuum port on intake is plugged with a pipe plug with teflon tape and all ports on carb are capped
 
Well then pull the plugs as they are likely fouled

Frankly, since you screwed with it, I'd suspect the distributor/ wires/ timing.
 
remytherat said:
Pretty sure ignition system is working. Rotor points to. #1 at tdc. wires are in correct order. plenty of spark
Click to expand...

And I assume
1) You know that there are TWO times in a 4-stroke cycle engine, when the piston is at TDC ..... right? Once on Compression and again on the Exhaust stroke.
2) you know that #1 cylinder is the driver's side front. and
3) to verify means to take that #1 sparkplug out and actually check for cylinder pressure.

If you knew all that, and did it right, then about all that's left is to check your cam-timing; it only takes one backfire for all the old, brittle, nylon teeth to be torn off.
 
remytherat said:
Screwdriver comment was sarcastic

Pretty sure ignition system is working. Rotor points to. #1 at tdc. wires are in correct order. plenty of spark

Pulled off the top of the carb. both bowls are filled with fuel. i believe the o rings are in place. Carb was rebuilt by previous owner i think but never ran

View attachment 1716159334

How and where are possibilities for vacuum leaks? This would have to be a huge one…
Vacuum port on intake is plugged with a pipe plug with teflon tape and all ports on carb are capped
Click to expand...
Try rotating the housing so the rotor is pointing between #1 and #8 terminals a little closer to #1 than #8.
 
92b said:
Try rotating the housing so the rotor is pointing between #1 and #8 terminals a little closer to #1 than #8.
Click to expand...
Why not do it right?

1...Remove no1 plug.
2...With finger stuck in no1 plug hole, bump engine until you START to feel compression. If you are unfamiliar, you may have to go 'round a couple times
3...When you start to feel compression, STOP and look for the marks which should be "coming up" Bump or wrench the engine NOT NOT for TDC but rather where you want the timing, AKA 8-10 or so for a stock cam, more for a performance cam
3...Insert dist so rotor points towards where the no1 tower in the cap will be. Rotate dist CW until points are closed or until reluctor tip is past pickup coil
4...Rotate dist. advanced (CCW) until points just open or until reluctor is about center of pickup coil
5..AS CRACKEDBACK has pointed out, you can also connect your timing light after installing the cap, and check the timing "on the starter."
6...Snug down dist a little to keep it in place and

START THE ENGINE.
 
67Dart273 said:
Why not do it right?

1...Remove no1 plug.
2...With finger stuck in no1 plug hole, bump engine until you START to feel compression. If you are unfamiliar, you may have to go 'round a couple times
3...When you start to feel compression, STOP and look for the marks which should be "coming up" Bump or wrench the engine NOT NOT for TDC but rather where you want the timing, AKA 8-10 or so for a stock cam, more for a performance cam
3...Insert dist so rotor points towards where the no1 tower in the cap will be. Rotate dist CW until points are closed or until reluctor tip is past pickup coil
4...Rotate dist. advanced (CCW) until points just open or until reluctor is about center of pickup coil
5..AS CRACKEDBACK has pointed out, you can also connect your timing light after installing the cap, and check the timing "on the starter."
6...Snug down dist a little to keep it in place and

START THE ENGINE.
Click to expand...
Nothing wrong with doing it that way either.
 
Thanks for all the advice. Timing was actually the issue. It had moved since I had set it because I didn't tighten it down enough. Eventually fired up. Had to baby it for a second and then got it idling well. Set timing to 9˚BTDC and drove it around. Flat spot off idle then surges at 1/3 throttle. Dead when the secondaries open. Time to mess with the four trillion doohickies on that carb.
 
Not enough initial timing for one thing.
 
remytherat said:
Thanks for all the advice. Timing was actually the issue. It had moved since I had set it because I didn't tighten it down enough. Eventually fired up. Had to baby it for a second and then got it idling well. Set timing to 9˚BTDC and drove it around. Flat spot off idle then surges at 1/3 throttle. Dead when the secondaries open. Time to mess with the four trillion doohickies on that carb.
Click to expand...
Yay. Thanks for reporting back. So often people don't.
 
Remy,
One thing at a time....& you will get through this:
- If the cam is stock [ or you are not sure ], set initial timing to 12*
- If the cam is bigger than stock, set initial to about 20*.
- With the engine idling, using a torch, look into the pri barrels, look from the brass booster tip down to the blades. If you see fuel dripping, that is a problem.
- Secondaries will NOT open until choke is fully open. So choke adjustment can stop secs from opening.

Report back after doing the above.
 
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