1985 Merc 115 in line 6

[rrumba]

I have a 1985 115hp inline 6 Merc outboard serial number A128532. the problem was it would die if trying to put it in gear for a hole shot. It would idle fine on the muffs but not in the water. I have rebuilt the carbs, replaced the floats, set the float levers to .4 and .04. I have checked the timing and verified that it is at 3 BTDC while cranking with all but plug one removed. I then cranked it and checked the max throttle for 23 deg.

I can get it to idle but it will die as soon as i put it into gear. I plan on making a DVA that is here on the site and i have found a CDI troubleshooting page but not sure if it is the right one. I am using the manual on boatinfo.no site as i do not have the manual. The on there is the one at the end as the others specify 4 cylinders or no cylinder count.

Does this sound like i am on the right track or did i miss something that i should do first?

Not really sure what i am checking for but will be reading up to see.

Any suggestions would be great.

 

[Bosunsmate]

Re: 1985 Merc 115 in line 6

Have you ever seen it running?
On that one can you back out a carb adjustment screw another half a turn?
My redband one would do the exact same thing and when i backed it out it went well

 

[rrumba]

Re: 1985 Merc 115 in line 6

Yes it was running and had no problems coming out of the hole and then on the way back in it just bogged down and would not plane out and then had a very hard time just idling in gear to get me back.

I have tried adjusting the carbs in and out small adjustments at a time and not help

 

[Chris1956]

Re: 1985 Merc 115 in line 6

First of all, I would doublecheck your timing settings, and link and synch using a Merc Manual. I do not think those are correct for an ADI ign Merc. Second of all, it is likely the idle mixture adjustment is too lean. After you verify (or reset) timing and synchronization, do an on-water adjustment. If she dies while trying to accelerate, open the top carb idle mixture screw 1/8 turn and try to accelerate. Repeat with mid carb and then bottom carb, testing after each adjustment. Repeat sequence if necessary.

 

[rrumba]

Re: 1985 Merc 115 in line 6

i will try and do the timing and link and sync again. after i have done them i have gone on the water to do an on water adjustment but it not make a difference. I will give it another try and see what happens. I have done 4 on water tests so no big deal and i will do another one.

thanks guys

 

[CharlieB]

Re: 1985 Merc 115 in line 6

Ran fine after the carb rebuild then started failing.

Do you have a water separating fuel filter?

Drain the carbs into a suitable container and look for any beads of water rolling around on the bottom.

 

[rrumba]

Re: 1985 Merc 115 in line 6

It was running then crapped out and then i did the carbs. while i was at it I also emptied out the old gas, replaced fuel lines under the cowling, installed an inline filter before the pump, rebuilt the pump and the Bayonnet connector as well to eliminate air getting in the line. No water in the gas or in the filter. Guess i should have added that to the beginning part. sorry about that.

I have done the link and sync about 4-5 times now and tried to do a water test as well but it would only die once it was put in gear

i can get it to idle and run until i put it in gear, then it dies.

sorry, this has been going on for about 3 weeks and trying to find a merc manual for a 6cly in line has been tough. I have been going through the search function and trying every thing i could find so i have forgotten a few of the thing along the way until i wrote down all that i have done and came up with the added info below.

Ok, i forgot, I did get it to run after the carbs were rebuilt for one short run but was having a problem with gas pouring out of the front of the carbs and from the bottom of the butterfly valve. This is what lead me to replacing the floats and adjusting the floats again. The old floats had fuel in them. is it possible that i do not have the floats adjusted correctly still? the instructions said from the top of the needle valve to the lever was .04" and from the seat on the gasket to the top of the lever when inverted was .4"

 

[Bosunsmate]

Re: 1985 Merc 115 in line 6

I always do mine by turning them upside down and seeing if blowing in there is shut off by the valve. Those textbook adjustments for whatever reason often lead to the flooding problem with me

 

[rrumba]

Re: 1985 Merc 115 in line 6

I have done that as well but have no idea if the float is cutting off as it should without some type of reference.

I have been reading the manual but it does not give a measurement for idle or for top speed fir the timing

 

[Chris1956]

Re: 1985 Merc 115 in line 6

Turn the carb covers (side bowl carbs) upside down. Bend the lower lever so that the upper lever is parallel with the carb cover. When right side up there should be about 1/4" space between the two levers. No fuel should leak from the carbs when motor is running, or you are gnetly priming the carbs.

Have you set the idle timing (I think is it 4* ATDC) when the carbs are just set to open? Max spark advance is 21* BTDC.

There should be a sticky with an inline Merc link and synch post from Clams Canino.

 

[rrumba]

Re: 1985 Merc 115 in line 6

i did the timing as the clam canino post had stated. even the link and sync.

i am at 4*BTDC and 21* for max as also stated in clam canino thread. I did not move the pointer but instead checked that when at TDC the pointer was pointing at 3* TDC.

When you say the lower lever to be bent so the upper is parallel when turned upside down, you mean the the lowest lever will be bent to make sure the upper one is even with the carb? Also, when right side up like it was going back on the carb, i am checking for that 1/4" gap at the end of the bottom most lever at the end of it to the upper one? does that sound correct?

I will be doing this once i get off of work today.

 

[CharlieB]

Re: 1985 Merc 115 in line 6

I don't see any mention of a spark test, have you checked for a hot blue arc at least 7/16 inch on every cyl?

 

[rrumba]

Re: 1985 Merc 115 in line 6

Another item forgot, yes i did check for spark with a gap tester and all 6 were good.

 

[mercurymang]

Re: 1985 Merc 115 in line 6

After re-reading the thread, you may need to just increase your idle speed a hair. From what I have read it runs ok, and it idles ok until you put it in gear correct. If so, do you know what your idle rpm is. I had adjusted my idle way day and it was great until i tried to put it in gear then it would die half the time. I bumped it up just a hair and now everything is fine. I have read that as your reeds get older, you have to adjust your idle up to compensate. I'm exactly sure why that is but I have heard it from several sources.

 

[rrumba]

Re: 1985 Merc 115 in line 6

that could very well be true, so i would have to turn the idle in cw some. it seems that the more i turn it out the worse it gets. but according to the link and snyc once the engine starts to die you turn it back and then add 1/4 turn and keep adjusting it. will try and do this also if i can get all done today.

 

[mercurymang]

Re: 1985 Merc 115 in line 6

No, I'm not talking about the carb, I'm talking about the idle stop. I'm not sure what yours looks like but i have an idle stop on the water jacket that I adjusted.

 

[Chris1956]

Re: 1985 Merc 115 in line 6

Idle speed should be no more than 900RPM, in neutral. Timing pointer should be set to .464 inches BTDC, when piston is .464 inches below TDC. Not sure what your post means about that.

I also think (but not sure) that idle timing should be ATDC, not BTDC for ADI ignition like you have. Best to double check. Carb lever adjustment is as you explained

 

[CharlieB]

Re: 1985 Merc 115 in line 6

As Chris is saying, idle speed adjustment is done with timing.

Idle mixture must be adjusted ON the water and IN Forward gear. Adjust to 'Best Idle Speed' from there the motor needs additional idle fuel mixture added to provide the additional fuel necessary for acceleration, almost another 1/8 turn fatter.

If the motor dies when shifting into gear, fatten up the idle mixture then begin perfecting the mixture with very small changes and allowing plenty of time for any excess fuel to be distributed thru the recirc system and burnt off before making another change.

 

[rrumba]

Re: 1985 Merc 115 in line 6

Turn the carb covers (side bowl carbs) upside down. Bend the lower lever so that the upper lever is parallel with the carb cover. When right side up there should be about 1/4" space between the two levers. No fuel should leak from the carbs when motor is running, or you are gnetly priming the carbs.

Have you set the idle timing (I think is it 4* ATDC) when the carbs are just set to open? Max spark advance is 21* BTDC.

There should be a sticky with an inline Merc link and synch post from Clams Canino.

Ok so yesterday i did this and then thunder and lighting hit so we called it quits. after re=reading the post i believe i did this backwards. I turned it upside down and set for the 1/4" gap and when right side up i had the top lever even with the carbs..... DOOH

So today will be to take them off yet again and fix this exactly as stated. what a retarded move that was.

 

[rrumba]

Re: 1985 Merc 115 in line 6

Idle speed should be no more than 900RPM, in neutral. Timing pointer should be set to .464 inches BTDC, when piston is .464 inches below TDC. Not sure what your post means about that.

I also think (but not sure) that idle timing should be ATDC, not BTDC for ADI ignition like you have. Best to double check. Carb lever adjustment is as you explained

As Chris is saying, idle speed adjustment is done with timing.

Idle mixture must be adjusted ON the water and IN Forward gear. Adjust to 'Best Idle Speed' from there the motor needs additional idle fuel mixture added to provide the additional fuel necessary for acceleration, almost another 1/8 turn fatter.

If the motor dies when shifting into gear, fatten up the idle mixture then begin perfecting the mixture with very small changes and allowing plenty of time for any excess fuel to be distributed thru the recirc system and burnt off before making another change.

ok, after pondering these statements i have to wonder if i am set up on TDC. I have gone through 12 revolutions of the motor to find out when no 1 is at TDC and every time i come up with being around 5-6* when no 1 is at TDC. I understand that it should then be set at 0 on the dial and turned CCW until it reads .464 which would make it .464" before TDC and then the pointer should line up with the mark of 464 on the flywheel. I cannot say that this is happening right now. Guess i need to go get a dial indidcator to verify it. Will try and get this done along with the carbs corrected as well.

if i am wrong in what i have stated please let me know.

thanks for all your help. and i was able to find a manual for this engine and download it, although it is still vague but it is a merc manual