I've been having an intermittent problem with my 2-stroke Merc 15 for a couple of years now. In the past it's occurred pretty rarely (once or twice a season) but has been happening more frequently this year. I've had it into the shop three times now and they seem to have just about run out of ideas. Would sure appreciate it if anyone here has a thought.
Here's what happens:
Motor starts fine and runs perfectly for a while (anywhere from 20-40 minutes) and then at normal running speed (say 3/4 throttle) it loses power. It doesn't die - it gradually slows down and you're left running just above trolling speed. Stop the engine and it will restart immediately, but the problem continues. Give it more than about 3/4 throttle while this is going on, and it will die (but will restart right away).
It will run like this for 15-20 minutes, then it'll cough and suddenly pick up and be back to normal - but only for a short while before losing power again. One time while I was stuck out there with it running this way I pulled the cowl off and looked into the carb - didn't look like much fuel was coming out of the jet. Then when it regained power you could see the fuel spraying out again. Squeezing the primer bulb doesn't make any difference.
A further wrinkle is that I've noticed that when it's lost power, I can get it to start running right more quickly by taking the cowl off and leaving it off. The hotter the day the sooner the problem seems to crop up, so I'm puzzled by whether it's really a fuel starvation issue or some kind of overheating issue.
So far the shop has cleaned and inspected the carb and fuel filter, replaced a torn bleed hose and fixed a loose ignition wire, but they've been unable to replicate the problem so they're just going on my description of it. I've run the motor using two different hoses (one brand new)and two different tanks, but regardless, if I drive around long enough this happens.
Before I take the motor back for a fourth shop visit I'd like to solicit some other opinions. Any help appreciated. Cheers!
Here's what happens:
Motor starts fine and runs perfectly for a while (anywhere from 20-40 minutes) and then at normal running speed (say 3/4 throttle) it loses power. It doesn't die - it gradually slows down and you're left running just above trolling speed. Stop the engine and it will restart immediately, but the problem continues. Give it more than about 3/4 throttle while this is going on, and it will die (but will restart right away).
It will run like this for 15-20 minutes, then it'll cough and suddenly pick up and be back to normal - but only for a short while before losing power again. One time while I was stuck out there with it running this way I pulled the cowl off and looked into the carb - didn't look like much fuel was coming out of the jet. Then when it regained power you could see the fuel spraying out again. Squeezing the primer bulb doesn't make any difference.
A further wrinkle is that I've noticed that when it's lost power, I can get it to start running right more quickly by taking the cowl off and leaving it off. The hotter the day the sooner the problem seems to crop up, so I'm puzzled by whether it's really a fuel starvation issue or some kind of overheating issue.
So far the shop has cleaned and inspected the carb and fuel filter, replaced a torn bleed hose and fixed a loose ignition wire, but they've been unable to replicate the problem so they're just going on my description of it. I've run the motor using two different hoses (one brand new)and two different tanks, but regardless, if I drive around long enough this happens.
Before I take the motor back for a fourth shop visit I'd like to solicit some other opinions. Any help appreciated. Cheers!