See If Anyone Knows The Answer To This One?????

[maineiac5586]

so, i have a 76 merc 500 and have been chasing a bog. I had a slight bog when hitting the throttle that i couldn't remove by adjusting the idle mixture screws. . I adjusted floats and reinstalled carbs, bog still there. all of this testing has been done with motor running on muffs. what i have been doing is standing back at the motor and revving it up by swiveling the plastic bar connecting the two carbs together. this is the piece that swivels between the carbs to open the throttle plates. i still had the bog when i swiveled this link. for some reason i decided to try to rev throttle from the control in the boat. motor revved right up with only a slight blip when hitting the throttle. what i can conclude is that by using the throttle in the boat i am also adjusting the timing when revving. just wondering if this makes sense to anyone? should engine rev right up with no bog when swiveling the throttle link connecting the 2 carbs?? thanks

 

[cell]

Re: See If Anyone Knows The Answer To This One?????

Yep.Your timing has to move when your carbs open.Preferably a tad more before.

 

[maineiac5586]

Re: See If Anyone Knows The Answer To This One?????

anyone else want to confirm this??

 

[Silvertip]

Re: See If Anyone Knows The Answer To This One?????

You are creating a problem where there isn't one! If you watch the linkage on the engine as someone moves the throttle on the control box you will see that the throttle linkage on the carbs AND the timing advance move in synchronization. Since you are simply flipping the carb linkage, the engine is seeing no timing advance, hence the bog. That is exactly why "link & sync" is so critical to good engine performance.. People tend to mess with these linkages without a service manual and can't understand why they can't get the engine to run right. This is a long procedure and must be done correctly.

 

[CharlieB]

Re: See If Anyone Knows The Answer To This One?????

Once again it just proves that old adage,

"When all else fails...... read the directions!"

 

[Chinewalker]

Re: See If Anyone Knows The Answer To This One?????

Also, running the motor out of the water with no back pressure can do funny things, too. Running on muffs in the driveway doesn't tell you a whole lot about the motor, other than it runs....

- Scott

 

[maineiac5586]

Re: See If Anyone Knows The Answer To This One?????

thanks, this is how we learn!!