Mercury 40hp 2-stroke starting problem

[CWH66]

Hello everyone, first time poster, first time caller, so forgive me if I leave out some important detail I should have included. This year my uncle passed away and left me his bass boat, a 2003 Bass Tracker 175PT with a 40hp 2-stroke Mercury, model 1041412AN, serial 0T639148, manufactured in 2002. I have fished countless hours on this boat but have never maintained the motor. Due to his slowly declining health, the motor had not been run in approximately 3 years.

I brought the boat home and started cleaning it out. I drained out all the old gas, as much as I possibly could and put in 7 gallons (1/3 tank) of new, ethanol-free gas. He always used mid-grade fuel with ethanol neutralizer added, and sta-bil at the end of the season. I hooked up the water hose, pumped up the ball, and lo and behold that thing started right up and I let it run in neutral for about 10 minutes. It had a little bit of a miss so I turned it off and removed the motor cover because I wanted to see what shape the plugs were in. The motor is clean as a pin, not a speck of dirt anywhere as he always kept it in a shed and covered.

I replaced the cover - and the motor has not started, or even act like it wants to start ever since. It cranks strong. I have looked high and low on the internet for advice and here's what I've tried and verified thus far:

Battery is fully charged (100%)
Safety lanyard is connected and switch is in the on position
All fuses on boat and motor checked out good
Spark plugs have good, hot spark - and are "wet" when I remove them after cranking
Checked the fuel filter, totally clean - and it filled back up easily when I pressed the ball, no kinks or issues I can see in the fuel line.

Following the starting procedure in the manual, I press in the key while cranking to activate the choke for 10 seconds - which is what I did first time I successfully started it.

Given what I've tried thus far, I am wondering if it's either a choke activation/switch problem or a carb issue. I am somewhat mechanically inclined, but given this is my first boat motor I'm hesitant to start digging in like I would another small engine on a lawn mower. I want to eliminate as many simple things as possible before digging deeper. Any thoughts? I have included pics of both side view, back view, and ID tag.

 

[airshot]

You should be able to hear the choke activate when you push in the key, so...is it working?? Did you actually check for spark on the pkugs? Weak spark does not work well. Plugs can create a weak spark once they have been fouled, try new plugs.. having sat for 3 years, could need carbs rebuilt, not just cleaned as that rarely works well. Keep us posted

 

[CWH66]

You should be able to hear the choke activate when you push in the key, so...is it working?? Did you actually check for spark on the pkugs? Weak spark does not work well. Plugs can create a weak spark once they have been fouled, try new plugs.. having sat for 3 years, could need carbs rebuilt, not just cleaned as that rarely works well. Keep us posted

Thanks for your reply. I will need to get some assistance to push the key in while I listen. I've been trying to find a service manual for this particular motor but the closest I can find so far is for a 3-cyl. Also I called our local parts store and tonight I'm going to pick up two brand new plugs. I did check spark, and it looked good to me, but I'm going to replace them anyway. I'll write back with what I find.

 

[CWH66]

Well, the situation is sort of resolved - just not *quite* to my satisfaction yet. I'm in a better and different place. So I verified the choke switch/solenoid was working, I can hear an audible clicking. I installed two brand new spark plugs called for by the engine ID tag. Pushed key in to choke and turned, no start. I felt defeated and went back to the manual for the 40th time. There is a footnote in the manual that says - if the engine is flooded, advance the throttle full forward in neutral and try to start for 10 seconds without choke. I thought to myself, how in the world can it be flooded when all I did was pump up the primer bulb and try to start once, but then I thought what the heck, not out of anything. Lo and behold, it fired and stalled. I waited about 30 secs, tried again, and the darn thing started (with throttle full forward, no choke). I backed it off to neutral and it stalled again. This time I advanced the throttle 1/2 way, and it started again. I let it run like that for about 5 minutes. It sounded a little rough to me and it didn't really want to idle as smooth as I would have liked. However, after about 10 minutes of 1/2 fast idle, I was able to return to neutral and idle without stalling, and I was able to go into forward gear without stalling.

Bottom line, the idle is a little rough and I would like to try adjusting it, but there are a couple of adjustment screws and I can't seem to find a service manual for this exact motor that would describe the procedure for doing this. I don't want to just start turning stuff I think the motor is running well enough that I can take it out locally and give it some exercise to see if it gradually improves. After all, it has been sitting for 3 years. So there you have it, got it running enough that I can try it out on the water. Going to play with it more tonight or tomorrow to see if it starts better now. If anyone has a link to the manual for this model, I'd be happy to purchase a download of it. Thanks for all your suggestions thus far.

 

[airshot]

If it flooded by pumping the bulb then look into float sticking or needle valve and seat leaking...fuel flow should stop there no matter how many times you pump the bulb

 

[Tech Tony]

Yes, after 3 years it could very well be a stuck float, or a partially dirty carb. Take a carb bowl drain plug out and see how the inside surface of the plug looks if its shiny and clean your OK. If it is scaley in any way clean the carbs.