'74 merc 650, update and further help needed.

[jbjennings]

Well,
Thanks to FastBullet I backed off the timing stop screw as suggested and I have no more pre-detonation problem. I think the timing still needs adjustment but it's not putting aluminum in my plugs anymore. The plugs are much cleaner now from oil as well. However, I'm still having a problem:
Upon getting back to the ramp, the motor boggs down and has no power when I try to put it on the trailer. If I try to give it too much throttle it will seem to flood out and die, or run out of fuel and die. I'm not sure which. It will idle on the trailer at an angle, but won't take throttle. If anyone has any ideas I'd love to hear them. Another weird thing is somewhere at midrange throttle it makes a kind of popping sound that has something to do with combustion being wrong. It's been doing this before the timing was changed.
Thanks,
JBJennings

 

[Faztbullet]

Re: '74 merc 650, update and further help needed.

Have someone pump the bulb and keep it firm while trying trailering it, if it helps reroute the water line thru the fuel pump as it may be vapor locking in pump.. there was a service bulletin on this years ago.

 

[jbjennings]

Re: '74 merc 650, update and further help needed.

Faztbullet,
It doesn't help to pump the bulb. Not sure where to look for the problem. Float adjustment?
Thanks for the help,
JBJennings

 

[Laddies]

Re: '74 merc 650, update and further help needed.

Try richening the low speeds and if that don't work adjust the carb pickup to to open a little slower.