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Mercruiser starts then quits...

Ok, time for an update...

I changed out the fuel pump. Same issue.

I connected a small gas tank with clear tubing to the inlet of the fuel pump. Same problem and I could observe the gas getting pulled down the tube.

I found out through my good friend "Youtube" that there is a fuel inlet filter at the carb. I pulled that out and found this:
fuelfilter.jpg

I though, "ahhh, found the problem." Replaced the filter. Same problem. Ugh.

So now, I disconnected the carb and going to take that thing apart tonight.
 
screen isn't bad but changing it would be good....indicates there's crud in the tank that could be 'polished out'. Still haven't seen where the pump's output pressure has been checked. Though mechanical pumps are reliable, they have a finite service life - the diaphragms stretch and the check valves do fail....Its also possible that there's enough residue in the bowl to clog the fill port to the accelerator pump's well....just get the correct kit is you opt to disassemble the carb...
 
I didn't check the pressure, instead opted to change out the fuel pump. Doesn't rule out a pressure problem I suppose.

Cleaning the carb right now.

I did notice that the manual showed the fuel inlet spring on the other side of the filter than was my configuration. I also saw a video on you tube that showed my config. Maybe it doesn't matter, but when I put it back, I'll err on the belief the manual is correct.

The coil still confuses me. I get 12 volt on purple and nothing the other side.

I don't really know how to check this part to see if it's good or not. I've been told they can't be checked reliably and should be changed out if suspect. Not sure if this case makes it "suspect" or not...
 
A very big thank you to everybody on this thread that attempted to diagnose my problem with my limited descriptive skills.

It's working! Yaay!

I pulled off the carburetor and gave it a clean. It seemed fine on the inside but I cleaned it anyway. I noticed that the float drop level was out of adjustment. For mine, it should be 27mm and this was about 40mm. I didn't think the difference would cause the problem, but I adjusted everything and put every back together. I also reversed the position of the spring and fuel inlet filter.

A few turns and it started up and ran just fine. I tried a few times and everything's in working order now.

So, thanks again and I'm sure I'll be back with the next issue! :)
 
Carb float setting is shutting off fuel to carb to soon.
Click to expand...

I pulled off the carburetor and gave it a clean. It seemed fine on the inside but I cleaned it anyway. I noticed that the float drop level was out of adjustment. For mine, it should be 27mm and this was about 40mm. I didn't think the difference would cause the problem, but I adjusted everything and put every back together. I also reversed the position of the spring and fuel inlet filter.
Click to expand...

You're welcome.
 
I've seen a rash of sticky anti siphon valves this season. Take makomark's excellent suggestion and hook up an outboard tank.
 
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