1979 inline 6 high idle

[1979checkmate]

Hello Fellow boaters,

I have a 1979 mercury inline 6 115 hp, (on a 1979 Checkmate Trimate-II.) I just finished replacing the stator, trigger, one switchbox, rebuilt carbs, rebuilt fuel pump (new diaphram). When i got the motor put back together, she fired right up, But had a Very high Idle (i am not sure how many rpm, as i do not have a tach on my test stand, but she was reving high) Last summer, i did adjust the idle stop screw to give a higher idle to the motor(this is before i replaced everything). But now that the motor has all of these new parts, it is overreving. So, i turned the idle stop screw back down to get the motor to a decent idle, which it did go down. However, the idle timing arrow is no longer aligned with the line on the throttle, it is just a little bit past. My question is, will i hurt anything by running it like this with slightly retarded timing in order to keep the idle revs down?

 

[Bob_VT]

Re: 1979 inline 6 high idle

Welcome to iboats.

Have you performed a lync and synch on the inline? They respond very good to that. Do not retard timing to make up for another problem.

Here is a great way..... http://forums.iboats.com/showthread.php?t=168855

 

[arsenalpsu]

Re: 1979 inline 6 high idle

I think you guys are talking two different things here. Checkmate is talking about "idle timing" which "is what it is" to get your idle where it needs to be, so yes you can (and should) retard it. I think Bob is talking about primary pickup timing. When you advance your throttle, do the carbs start to open when your arrow lines back up? If so your are fine.

THIS IS ASSUMING everything is linked correctly, so when your arrown lines up and your carbs open you are at the correct timing # as per your OEM book.

 

[CVX20SPRINT]

Re: 1979 inline 6 high idle

X2 on the lync and sync

 

[1979checkmate]

Re: 1979 inline 6 high idle

Thanks guys, i will do the link and sync, but also retard idle timing if need be after the link and sink. I didnt make any timing changes or anything before removing everything, so i assume it should still be about right other than the idle timing (because i did adjust that last year), but i will do that, just as soon as i pick up a timing light. Would it be safe (and effective) to do the link and sync at idle with water muffs? I dont have a test tank, so if one is necessary, i suppose i will just take the motor to a marine mechanic to have it done. (which would suck because i take pride in doing all of the work to my boat) But i will do what i need to do to get her back in tip-top running condition.

-'79mate

 

[arsenalpsu]

Re: 1979 inline 6 high idle

You can set the timing with out her running, just with the starter cranking. (you have a CDI ignition right?) The carb adjustment must be done on the water for the correct back pressure- any mechanic who says otherwise does not know the I6 motors.