Jeremy Loc: America

If it runs constantly after it starts it’s probably not fuel delivery but you really need to narrow down what is causing it.

bitemybass Loc: Massachusetts

Awesome really appreciate that thanks

Mike-1000 Loc: SE Mn. Between Winona Mn. and LaCrosse Wi.

Are you sure it’s a fuel problem? have you physically checked for spark at each of the plugs? What color are the spark plugs burning.

Jeremy Loc: America

Exactly. I said same thing. He needs to do it ( what you suggested) when the symptoms are happening. I remember another guy on here had a bad distribution box on his Merc. Intermittent and mostly after it’s warmed up. Could be dirty or bad wire on primary side of electronic ignition etc. I am not even sure if choke is being activated during start mode but I explained all that.

bitemybass Loc: Massachusetts

Yes I did I removed all 3 and tried starting it and had very nice blue spark from each one

Ivey Loc: South Central Tennessee, Tim's Ford Lake

I'm clueless, Air, clean Gas and fire should equal a running motor. a bad Stator can cause the problem you are describing, once they warm up the fire is reduced and causes a bad start. I don't know how to tell you to check it because it may deliver some fire but not enough to run correctly. I think a Merc. has them inline of the spark plug wire so there's more than one.

Frank romero Loc: Clovis, NM

I had similar problems with a 40hp Mercury. Changed in line filter and didn’t have problems afterward. Hope you work it out.

Ivey Loc: South Central Tennessee, Tim's Ford Lake

Just thought of a problem a friend had, his gas lines were old and the alcohol in the gas now day were breaking down the gas lines. Very small particles of this stuff would clog the injectors and cause that problem. He changed out the old lines in the motor and never had that problem again.

Ben Bragg Loc: Dayton Ohio

My brother just went they the same thing.
Ended up the new fuel line had collapsed inner liner.
Was able to cut off a foot , reconnect and runs like a champ ever since

This was a new line installed a couple years prior , but never run

Harpoon Loc: South side of cape cod

Check solenoid

Fishin' Musician

I might be the guy Jeremy is talking about. I have an '86 50hp Merc which had a problem running in gear at low rpm. Thanks to all the guys on this forum, the number of things that might have been the cause were narrowed down to the switch box.
Recapping what I've read so far in this thread...
- The engine runs with muffs, but then it will will not run after shutting off for a short period, even though the flywheel turns.
- You've checked all plugs, and each has a good blue spark.
- Your fuel is pumping into a cup with no issue.

Have you been able to get it to run in the water? If so, did you put it in gear and have it run for any amount of time?

I ask this, because my problem was that I could get it running, but most of the time, it would kill as soon as I put it into gear. The times that I was able to keep it running in gear, it would run fine a full throttle. What was happening, was the spark was enough to get running, but not strong enough to maintain it under load. Only when I was at speed did the spark get strong enough, but as soon as I slowed to 5mph, it would kill.

I used a multimeter and did a thorough check to eliminate the rectifier, stator and trigger, leaving the switch box as the problem. Quick and easy swap and I've not had a problem since (knock on teak).

I feel you should do a similar diagnosis. If you have the manual, it should give the values that each component should read on the multimeter.

If all that checks out, you might need to get advise on the reed valves. It came up in my troubleshooting, but since I didn't do any work on mine, I can't offer any suggestions. I'm sure Jeremy and others here have reed valve experience, and can weigh-in on that possibility.

Grizzly 17 Loc: South central Pa

[quote=bitemybass]I have tried that a few times and it still didn’t start. I also have waited a whole day and tried on a cold start and still wouldn’t run[/quot. Do you have remote fill on your boat. If so make sure that vent is working properly. If the primer bulb is hard to squeeze get a new one. You really should run non ethanol n a water separator filter. I use stabil n fuel treatment all the time. Your choice

bitemybass Loc: Massachusetts

Thanks guys. I actually was able to get it started today multiple times on the water. It turned out I had to push the key in for the choke for Atleast 10-15 seconds and that would start it sometimes. And other times I had to move the throttle in neutral to about half way and choke it for 5-10 seconds and it would start. I’m thinking an issue with choke not sending enough fuel to middle and bottom carbs. Once I got it started it ran great. I do have it going to my mechanic in a couple weeks for him to go through the entire motor.

Grizzly 17 Loc: South central Pa

Ask him what he thinks about the water separator 👍👍

bitemybass Loc: Massachusetts

Will do