outboard starts, goes WOT, then dies, and wont restart

[graffix989]

got an outboard from my dad, its been sitting unused for the last 4 years. its a 1980? 1cyl, 2-stroke, 4hp... figured it was a simple engine and nothing major would need to be done. after looking a little deeper i realized what 4 years in a shed would do. I replaced all fuel lines and new primer bulb. replaced a vacum line that runs from the top of the head to just before the carb, no idea what that does. installed a pump kit, that came with new diaphrams. replaced reed valves, and houseing gasket. torn carb completely apart and cleaned, no noticable wear on the main, pilot, float needle. float floats. the only thing i did not do is check the float level... i do not have the info for that. so on to the problem.....
after being left alone for a bit, on the 3-4 pull it will fire up and take off WOT, even tho the throttle is at approx 1/4. screams for 2-3 seconds then dies. and will not restart for another 10 minutes.
so im thinking a flooding issue right? took a look in the bowl and the float is only sitting on enough fuel to fill maybe 1/3 of the chamber. This is a hard engine for me to look at while turning over because the pull cord mech is apart of the cover assembly. oh and i pulled the new spark plug and looks like a small amount of fuel pooling just on the bottom edge of contact surface... again pointing to flooding. please help

 

[CharlieB]

Re: outboard starts, goes WOT, then dies, and wont restart

Float level should be near perfectly level with the carb held upside down.

Have you rebuilt the fuel pump?

Remember this motor is a 2 stroke, just like a weed-wacker or chain saw, it likes a lot of choke to initially fire, then needs a fat mixture until it warms up a bit.

Starting with full choke and the throttle turn to the start range, the motor fires and races, turn OFF the choke, but be ready to 'bump' the choke again when the speed begins to slow too much., just for a heatbeat, not even a whole second. Once the motor warms and the speed evens out then you can turn the throttle back down to idle.

Spark plugs should have just the slightest smell of fuel, most of what you are seeing is unburned oil, without it the motor would soon grind to a halt.

 

[graffix989]

Re: outboard starts, goes WOT, then dies, and wont restart

yes fuel pump was rebuilt. i will have to check the float level trying that thx

however, the engine shouldnt race to WOT without the throttle being open should it??? even with the choke on it just tries to rev up to the max. the throttle seems unresponcive. but all the mechanical parts seem to be moving (carb plate, timing plate)

 

[graffix989]

Re: outboard starts, goes WOT, then dies, and wont restart

and let me clarify a little. when i start it with the choke on and throttle 1/4 past start it fires and the engine goes(not the throttle) WOT. of course the choke will not let it open up all the way, so it boggs at a certain point. open the choke and it races full board til it dies.
the motor WILL NOT start with the throttle on the "start" position.... ive never seen an outboard this old start on the "start" position acualy

and this all lasts maybe 2-3seconds at the most. then will not start again until it sets for a while. no matter how many pulls

 

[h2opdler]

Re: outboard starts, goes WOT, then dies, and wont restart

I am a new boat owner of a older boat and I am having similar problems. I have not taken anything apart except disconnecting the gas line from the tank. Also I dont understand what "WOT" means in "outboard starts, goes WOT, then dies, and wont restart"



just bought my first boat yesterday a 1984, 16 ft Lund with a 40hp Mercury outboard. It ran fine I took it for a test drive and had no problems at all, it started right up idled fine, ran well,no problems at all. I puttered around with it when I got it home disconnected the gas to check out the gas can storage area, reconnected it and left it alone.
I registered the boat this morning and put it in the water. It started fine. I idled through the no wake zone for about 100 yards and it stalled. I tried to start it and after a couple of tries I realized that I forgot to squeeze the primer ball. Gave it a squeeze and it started,went another 100 yards and it stalled again. I could not get it going after that. It would start and choke itself out. After 30-45 minutes I gave up and used the trolling motor to take me back to the put in. Did I buy a P.O.S. ? Did I do something wrong? I have absolutely no experience with outboards and dont know where to turn. Does anyone have any suggestions on what I did wrong and how to fix it ?

Thanks in advance

 

[graffix989]

Re: outboard starts, goes WOT, then dies, and wont restart

WOT = wide open throttle
ur situation sounds like fuel starvation, possible fuel pump needs to be rebuilt. was the engine realy hot when it died? i assume u didnt replace the water impeller? it may have just overheated as well.... but please start a new post with your problem because this is completly different from this post

 

[h2opdler]

Re: outboard starts, goes WOT, then dies, and wont restart

Thankyou,
I was thinking it was more of a flooding issue, but I could be wrong. I think I will need to bring it to a mechanic and have him check it out. thanks again

 

[graffix989]

Re: outboard starts, goes WOT, then dies, and wont restart

so I finaly figured it out and i thought i would share. It was a faulty ignition coil. it would just constantly fire no matter what signal it was recieving from the flywheel. This would overheat the coil and make it stop function completly after a few seconds and not work again until the coil cooled down. I tested this by letting it sit over night then measuring the primary and secondary resistance levels, got aaprox 0.50 ohms. tried to start it, it fired up and raced off to WOT then died (like it has been doing all along). so I took a second measurement now that the coil was hot. Nothing, not even continuity. So i replaced and went out on the water for 6hrs without any problems.