Good evening, what started out as a smooth operation has turned into an extremely frustrating endeavour. I need some outside counsel before I lose all my hair. I bought a boat with a blown motor - a 5.7 LX non-vortec with a 4 bbl carb. I replaced it with a 5.7 long block with Vortex heads. It is in the boat and all wired up but I cannot get it to start. I also converted it to an electric fuel pump - a carter universal marine pump #4389. New plugs, new wires.
It cranks, sometimes coughs, occasionally sneezes back out through the flame arrestor of the carb. I set the timing with the engine on a stand before it went into the boat. I used my compression gauge - when it started to read, I lined up the 0 timing mark. Dropped the distributor in and noted where the rotor was pointing and installed the cap and wires with #1 wire going on the terminal that the rotor is pointed at. Definitely backfired with a bang in this configuration. Few pops out the exhaust as well.
I checked for spark. Unfortunately I had no helpers so the only way I could do this was by watching the strobe of a timing light as I cranked the engine. Strobe goes off so this indicates to me that there is indeed spark.
Fuel is a little harder to determine but I believe it is getting fuel. I can manually open the throttle and can see the accelerator pump squirt fuel, as well I can smell fuel once I give up on cranking. The boat was sitting for a while with a full tank of gas.I think it is bad - it is an awful yellow colour and smells extremely strong.
I reset the idle screw and idle mixture screws as per the manual (idle screw touching the base plate, mixture screws 3 rotations out from being seated)
While in the boat, I rechecked the timing, this time just using my finger over the spark plug hole. Got the same rotor position. This time I tried advancing it and set it to 5 degrees BTDC. Coughs more like it wants to start. I pump the throttle a few times and set it higher up. The engine caught and ran for maximum 5 seconds before fuel sneezed (or backfired, wasn't a loud bang) out the carb and it stalled.
I did disconnect the fuel tank and hooked up a portable tank with fresh gas. Problem is - I can't remember if I got the engine to run for that 4-5 seconds using the portable or main tank. Regardless, moving forward I will only use the portable one until I can get it verified running in the driveway. I think the main tank has something like 60 gallons in it - draining that will be fun...
Then I read somewhere online that it is possible to feel air out the plug hole on the exhaust stroke as well. This made me wonder if I was indeed 180 degrees out. Am I losing my mind?
The backfire/sneezing seems to suggest a timing problem, but I really think I set it properly. Could it be a fuel problem (carb needing rebuild?)
It cranks, sometimes coughs, occasionally sneezes back out through the flame arrestor of the carb. I set the timing with the engine on a stand before it went into the boat. I used my compression gauge - when it started to read, I lined up the 0 timing mark. Dropped the distributor in and noted where the rotor was pointing and installed the cap and wires with #1 wire going on the terminal that the rotor is pointed at. Definitely backfired with a bang in this configuration. Few pops out the exhaust as well.
I checked for spark. Unfortunately I had no helpers so the only way I could do this was by watching the strobe of a timing light as I cranked the engine. Strobe goes off so this indicates to me that there is indeed spark.
Fuel is a little harder to determine but I believe it is getting fuel. I can manually open the throttle and can see the accelerator pump squirt fuel, as well I can smell fuel once I give up on cranking. The boat was sitting for a while with a full tank of gas.I think it is bad - it is an awful yellow colour and smells extremely strong.
I reset the idle screw and idle mixture screws as per the manual (idle screw touching the base plate, mixture screws 3 rotations out from being seated)
While in the boat, I rechecked the timing, this time just using my finger over the spark plug hole. Got the same rotor position. This time I tried advancing it and set it to 5 degrees BTDC. Coughs more like it wants to start. I pump the throttle a few times and set it higher up. The engine caught and ran for maximum 5 seconds before fuel sneezed (or backfired, wasn't a loud bang) out the carb and it stalled.
I did disconnect the fuel tank and hooked up a portable tank with fresh gas. Problem is - I can't remember if I got the engine to run for that 4-5 seconds using the portable or main tank. Regardless, moving forward I will only use the portable one until I can get it verified running in the driveway. I think the main tank has something like 60 gallons in it - draining that will be fun...
Then I read somewhere online that it is possible to feel air out the plug hole on the exhaust stroke as well. This made me wonder if I was indeed 180 degrees out. Am I losing my mind?
The backfire/sneezing seems to suggest a timing problem, but I really think I set it properly. Could it be a fuel problem (carb needing rebuild?)
