Alarm and "Flat Spot" Trouble with my first Used Boat

oldsearay

Cadet
Joined
Aug 3, 2003
Messages
6
It is an '88 Sea Ray with a 100hp Merc. Outboard that was not used much in the past year or so. Had an earlier post, but I think I now have a bit more understanding of the problem.<br /><br />First it had what I now think are called "flat spots" (now that I have this Clymer manual that does not help much). Basically starting off it would have a lot of trouble getting going. Even with at full throttle it would not get close to plane. Then it would have "awakenings" where it would jump up into cruising speed for a while and then all of a sudden, the engine will back off about 1500 rpms for a minute or so...but if you leave the throttle forward, after a short time it will just kick back in to cruising speed again.<br /><br />Did some tinkering with the top carb (didn't know there were 2 at the time) "low speed mixture screw" and thought I kinda solved that problem. When you went full throttle, now it would move. But then, a lovely screeching alarm (constant beep) would sound the first time I would get it moving after getting out of the no wake zone, and wouldn't go off till I killed power.<br /><br />Was told the alarm could be from a mixture that is too lean that is making the engine run hot but the temp gauge does not get over 140 (if it works right). Armed with my manual I adjusted the mixture screws and took it out, and now it has both problems. Long "flat spot" spells and an alarm to go with it. So I have two questions...<br /><br />1. How do I adjust the mixture to make it richer (tighten or loosen the screws), and could that be the big problem?<br /><br />2. Any other pointers? I'm at a loss and not having any luck finding even a bad mechanic to work on it. (But I am handy with the right direction).<br /><br />Thanks to everyone in advance for their input...<br />David
 

The Marine Doctor

Commander
Joined
Jul 25, 2003
Messages
2,177
Re: Alarm and "Flat Spot" Trouble with my first Used Boat

The low speed jet should not have a bearing @ full throttle.<br /><br />with that said...to lean it out...Clockwise...to richen counterclockwise.<br /><br />Check compression and spark<---do this first.<br /><br />Check to see if the oiler is sinc'd properly.<br /><br />Rebuild the accel pump.<br /><br />Rebuild the fuel pump.<br /><br />TMD
 

oldsearay

Cadet
Joined
Aug 3, 2003
Messages
6
Re: Alarm and "Flat Spot" Trouble with my first Used Boat

On the lean clockwise and richen counterclockwise, that is the 2 mixture screws on the 2 carbs, right? Just want to make sure it isn't some other screw I am unaware of..<br />Thanks!
 
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