96' Hewes Bayfisher 18 Engine Trouble

[jmr77]

'96 Bayfisher is powered by a '96 115 Mercury 2+2.  I'm experiencing a fuel starvation issue it seems.  It happens at idle and also when up and running.  At idle, it runs through the fuel in the primer ball +/- and then wants to stall.  When I get up and running, it seems to run a bit longer at times and then bogs down, often to a stall.  I've noticed that if I keep pumping the primer ball it will come back to life.  I've recently done the following to try and address the issue:

1. Changed out the primer ball
2. had the carburetors rebuilt and serviced by a trusted mechanic.  I needed the boat on a quick turnaround so he did not water test it (regret that now).
3. When I got the boat in the water it did the same thing it was doing.  It was running better when running, but still repeated the issue
4. Based upon that, I changed out the fuel pick up line.  I installed a new pickup tube and anti-siphon valve
5. confirmed the vent line was clear
6. In troubleshooting the issue, I came to believe that the problem was a failed or failing low pressure fuel pump.  I picked up the fuel pump repair kit and changed the parts out.
7. I was sure after replacing the pickup tube, anti-siphon valve, repairing the fuel pump (and oh year, recently replaced the fuel filter) I had it sorted out.
8. Took the boat to the water, and same issue.  

I'm running out of ideas but suspecting:

1. I didn't handle the fuel pump repair correctly.  This seems unlikely as it was pretty straight forward and it's basically doing the same thing it was before
2. Need to adjust the idle on carburetors 1 and 2.  I was told to loosen them by an 1/8th of a turn?
3. I was also told with the primer ball in place, I don't need the anti-siphon valve?  This concerned me since I've read on other strings that needs to stay?  I'd like to pull the bearing or replace with a standard barb but wanted to see if I could get some feedback first?

Appreciate any suggestions.  Thanks

 

[Toeknee217]

Those 2+2s are known to have pretty rough idle up until the other cylinders kick in. I believe you are on the right track since it runs better when you pump bulb. I would've suspected the fuel pump or primer ball as well given that info. Check for air leaks at all the connections leading up to the fuel pump.If you haven't already done so, inspect your spark plugs to see how they're burning and replace them to start clean. Buy a manual for your model and go over all the carb adjustments.  Some of these older outboards had plastic adjusters that would wear out and undo themselves. At least my old Johnson from that era did and it would cause the engine to stall while under load. Id also check to make sure the coils are all working since it seems to run sometimes longer than others. Could be getting intermittent or weak spark.

Good luck 

[polliwog]

Check the anti siphon valve, there have been many issues with these things.  I wouldn't have one If it was my boat. Older boats didn't have them when they were new.  My 1997 Hewes LT doesn't have one and I've never had a problem with my fuel or fueling.