1985 Merc 115 in line 6

[CharlieB]

Re: 1985 Merc 115 in line 6

The old cork floats should be tossed out and replaced with the newer plastic floats. The cork will saturate with fuel and sink, allowing that carb to flood.

ANY fuel leak MUST BE found and repaired.

Idle timing may be anywhere within the range of 2 to 6 degrees After TDC. The actual # isn't critical, it is the idle RPM that is important. Idle fuel mixture MUST BE sufficiently fatter than 'Best Idle Speed' while in gear to provide sufficient fuel for crisp acceleration. Once up to speed the motor is off the idle circuit and running only on the main jet. Make sure they are clean.

After all repairs and carb adjustments are perfected then you need to find out your WOT RPM. Motor mounting height on the boat will make a difference in RPM, as will trim angle.

Once you have a real WOT RPM then you can look into prop selection to finish dialing in the motor to allow it to operate within the recommended RPM range.

 

[rrumba]

Re: 1985 Merc 115 in line 6

My mercury manual (downloadable)

Pop, where might that be?????

 

[rrumba]

Re: 1985 Merc 115 in line 6

daves,
thank you for the response. the 4k might be limited right now because the issues i am having, no? possible? mabye? I have replaced the floats due to gas intrusion, rebuilt the carbs to include new seats and needles and the missing gasket between the carbs and the block. I have found 4 different methods for how the carb float tabs should be setup and have tried all of them multiple times using the invert method and straight across and using calipers to measure the gaps. I no longer have gas flowing out the front of the carbs so that is a big + and a step in the right direction as well as another issue resolved awhile back.

i hear what you are saying about the prop and will address that once i can get her to run. The floats are not fun ones to adjust especially since there are no "SET" hard lined directions.

Please stay tuned and continue to throw suggestions at me, good or bad, double or tripple checking. IT IS ALL APPRECIATED.

 

[rrumba]

Re: 1985 Merc 115 in line 6

Chris, Charlie, Dave, Thank you all for your continued help with this, this is why i love this forum, you guys stick by, albeit painfully i am sure, to help us less knowledgeable ones out and not just throw out there use the "SEARCH" function and then get back to us. It truly is appreciated.


Tonight i was able to take it out to the lake and put it IN THE WATER while still strapped down to the trailer. I believe someone might have mentioned that IN THE WATER is the best place to set it, so i heeded that suggestion and away we went. now bare with me as this may get confusing, absolutely long winded and most definitely unconventional.

So first thing was to get the carbs adjusted and running without bogging down. i adjusted them and got them to run smooth by turning the carb linkage that connects all 3 together and not the arm the cable attaches to. Now the carbs are adjusted so they will idle and run up at full throttle. Next was to try and do the same while on the linkage arm. Now this is where it got screwy. I could get it to run some times and then it would not. made sure all was adjusted correctly and kept going. it would not stay running at idle in gear.

if i pushed the timing linkage under the flywheel just slightly to the rear it would stay running in gear. I figured it was due to timing so i loosened both set screws and put it in gear at WOT and adjusted the high screw until it ran like i would have thought it should by ear. Kind of like adjusting timing on an old chevy. once that was done then messed with the low end set screw for a bit until it stayed running just in gear but at idle. kept giving it hole shots and then easing back off, hole shot then quickly returned to idle, not neutral, then did some more testing from hole to in gear idle to N to hole etc etc etc. Now it was running at idle in N, hole shots were quick to respond and sounded crisp/right.

now figuring we GOT IT! finally shut her down waited about 15 minutes, kind of like out fishing then moving spots. fired her up again and back to the same issue. DOOOOOHHHHH. Then started looking at things some more and watching EVERYTHING move. I noticed that the linkage that is spring loaded under the fly wheel up front seen in the link below, parts 19-22, were sticking. they did not move free at all. I was expecting it move around like the lawn mower engines without throttle cables but with springs that kind of adjust themselves. this was not happening. if i nudged it stern just a bit the it would engage and run like it should. if i put slight pressure on to the from the front pushing to the back while my son ran through our testing N, Hole, idle, N, idle, hole etc it was working again. i thought maybe a spring is missing that should be pulling it backwards but looking at the diagram that is not the case. when he would come back from being in gear to N and try a hole shot it would bog down and die out unless i nudged it. It was sticking forward and when that happens it would not even stay running in idle.

Now i could be wrong so Help me out here....... there is a lot of play/slack in the assembly and it does not move freely at all. it binds up and feels like it is sticking a lot. My thinking is that this may be my issue. but i do not know if it might be the internal spring or if i should just install an external spring hellp pull it backwards. I would rather fix it the right way. If i seem like i am off base here pleas let me know. How do i go about fixing the slack and binding up in this part? should i just take it apart degrease it and then lube it again. THat i will probably do anyway as it just seems like good maint/preventative maint. if it is the internal spring that is weak or stretched/worn, where can i get another one?

If this seems logical please let me know or if i am chasing my tail, how about another bone so i can stop running in more circles :facepalm:

LOOKING FORWARD TO AND AWAITING the response from the GURUs.

Thanks guys.

 

[popknot]

Re: 1985 Merc 115 in line 6

Here is a link to the post where I got my manual. $4.95 says its a merc manual in ad. Its pretty good, pics are a little fuzzy, but does have some good info. Although it lists the primary pickup timing at 4-6* BTDC in the appendix and I think thats wrong. Should be ATDC. It does cover several different models also 1965-1989. 90-300 hp. But overall for $4.95 not bad.

http://forums.iboats.com/mercury-mariner-outboards/oem-shop-manual-560761.html

Also here is a link to a previous post with some pics of pages from a mercury manual that I thought gave a good detailed step by step link and sync.

http://forums.iboats.com/mercury-mariner-outboards/idle-fine-tuning-1988-115-l6-413324.html

Notice the primary pickup timing listed (5-7*ATDC)

 

[popknot]

Re: 1985 Merc 115 in line 6

Not sure what the spring you are talking about is. Couldn't see the picture. But if its something connected to the linkage to the trigger and thats not moving back and forth freely that would cause a lot of problems. That HAS to move freely and advance and retard the timing in sync with throttle positions. But I'm not the guy to give advice I'm still seeking advice myself. These other guys will get you through it, I'm just listening in as I'm going through some similar stuff with mine. Good Luck John

 

[rrumba]

Re: 1985 Merc 115 in line 6

ok so the pic is now working, sorry about that. the spring i am talking about is the internal one in the assembly. that is what i will be working on today to see how i can get it to move freely. Got the manual as well.

 

[GA_Boater]

Re: 1985 Merc 115 in line 6

RR - Your image is small, so I re-posted a larger one. Looks like you're on the right track. Couple of things. Is the spring pre-tensioned? I don't have a manual, so this is just an idea. The other thing is all the pivot parts from item 25 (bolt) on down could have old hard grease making it hard to return. I only mention that from experience on my old Merc. Git 'er done. You're almost there.

[URL=http://s1184.photobucket.com/user/sv29n/media/Cheap%20boats/115link.gif.html] [/URL]

 

[CharlieB]

Re: 1985 Merc 115 in line 6

The throttle/timing lever is PUSHED back against the stop by the throttle cable. The throttle cable should be adjusted so it has a small amount of pressure pushing against the idle stop.

Clean all pivot points and very lightly lube with a very light weight grease, or dry silicone spray. Heavy grease can thicken in cold weather.

 

[rrumba]

Re: 1985 Merc 115 in line 6

Ok, the saga continues. BUT, i think i am getting closer...

Yesterday i took apart the linkage and what i found was that the internal spring was not hooked around the top half of the clamp. so when it should have been under tension it was not. Cleaned it all up and greased it, put it back together and it was functioning how i thought it should. there is tension now and it returns and pulls as it should.

So with that working correctly, timing was next, again. reset it all, leave the carbs set as they were, hoping it would work. took it to the lake and messed with it for a bit. fired right up, yeaaahhhhh :laugh: looking good...... hit the hole shot just to see and bogs down.... :blue: kind of expected that anyway. So start the carbs again and then what do i find..... gas pouring out of the bottom carb. looks like the float is stuck now, unsure why. But before that my son asks should there be water coming from the top spark plug???? NOOOOOOOOOoooooooooo....... but alas, there. upon further investigation it is not coming from the spark plug but just below it where the cover mates up with the powerhead(???? not sure if that is the right location name) but to me would be the valve cover to the block on a normal engine.

So back home we go. after looking at pics it could just be that the gasket has failed, hopefully the cover or nothing else is warped. Compression is still good on all cylinders as well. Today we were goint to take off the carb and check it but the weather is not letting that happen at all.

So now we have the carb to get corrected and could it just be a new gasket is needed for the cover over the spark plugs or do i need to do more involved checks? it is not running hot, the water coming from the tattle tale is warm/cool but not hot.

another thing here that i believe i have created myself and am rather retarded feeling is that i think i have the timing wrong. When i set it up I did not think anything of it, but looked at the marks that were already there and someone before me had made a paint mark on the 5* mark so i was using it. after thinking about it last night, it should be 3-5* BTDC and on the front plate of the motor it has a sticker that says 4* BTDC, now where the 5* mark already made is on the right side of the 0 mark which would make it 5* AFTER TDC and not before. so now i have to correct the timing again, no biggie, then run through the link and synch again after i get that the gasket replaced and the carb issue resolved.

does anyone have a torque sequence and specs for the bolts by chance? my manual give a general sequence that basically states start in the middle and work out alternatively.... I have 85in lbs for Torque and 1-3* BTDC in the manual for timing

Man do i feel like dope right now with the timing and not catching that i am setting up for after tdc instead of before. Talk about brain flatulents........ :embarassed: :joyous:

 

[CharlieB]

Re: 1985 Merc 115 in line 6

Relax, you are still on the right track.

If you haven't installed plastic carb float and carb kits now is the time. If you have then either crud got in or the float adjustment isn't perfect.

The water cover is just a cover that keeps cooling water in place, it only needs a gasket. WARNING, those old 1/4 - 20 bolts have a terrible habit of seizing and breaking off. I love my 1/4 inch air gun turned down to about 1/2 power, it doesn't just forcefully turn the bolt which often just break it off, but it 'rattles' it which tends to break the crustys on the threads, allowing the bolt to screw out . I still have my share of broken ones and resort to getting out the drill.

Idle timing isn't set in stone, the range is only a guide, every motor is slightly different.

The ATDC mark is about where the carb butterflys should begin to open. Called throttle pick-up point in the book. As the control arm pulls the cable the linkage begins to advance timing, there is a small gap such that timing advances before the throttles actually begin to open.

 

[rrumba]

Re: 1985 Merc 115 in line 6

trying to track down the right gasket now. thanks charlieb

 

[rrumba]

Re: 1985 Merc 115 in line 6

alright, i have the timing set to 4* BTDC this time and not AFTER. Gasket is on the way for the cylinder cover (?) and carbs come off tomorrow to check the float levers.

Since i am doing the floats again, what is the best method for setting the levers?

 

[dethalis]

Re: 1985 Merc 115 in line 6

Might I add that I have about the same year merc 115 and it to ran fine first time I took it out after I had changed plugs, fuel filter, primer and all new non ethanol fuel. The second time it ran fine to get us to this island on the lake near us. Then when trying to leave itbwould not get plane.. it to idles fine but will also rev up fine in nuetral. If I putnin gear and give gas dies.. so Inoticed as I tried to tinker and figure out what it was that day that I had raw fuel drops comming from the two rectangular exhaust ports on the back of the engine hitting the water... I am now to the point its either the fuel pumps or lost compression or carbs... I am going to check my compression because without this the fuel pumps dont operate on this engine. If that is good and I have good spark it eill probably be a fuel pump diaphram so I will be rebuilding those... I suspect you could have a similar issue and I would hate that you spent so much time on it if it was that easy or if the compresion is down... I would also check these things...

 

[dethalis]

Re: 1985 Merc 115 in line 6

Sorry just re read the first page of the post... ok so if you have rebuilt carbs and pumps try checking your compression. . If that is not right it will not pump fuel properly and will thus need a block rework to correct..

 

[rrumba]

Re: 1985 Merc 115 in line 6

dethails,
Thanks for the post and suggestions. I have checked and continue through out the process as it's easy enough to do at the same time, and they are all good, around 120-125.

Got the gasket in today and replaced. Did the carb floats again by turning them upside down and aligning with paralell to flange. turned upside down and blew into it to check that they were shut off and they were. So all good to go and time to try it again. Off to the water we go. adjust here and there with the cabs etc. now if i hit a hole shot while strapped to the trailer still, it gets to about 3500 rpms and will run. i can come off slowly and it will continue to run in gear and in idle, only if i come up slowly. if i just put it in gear and idle it will die, if i come from WOT straight to idle it dies. I was going to adjust the timing some more to about 5* BTDC but ran out of gas :facepalm:

So tomorrow when i get more gas in her, back we will go and try to adjust the timing a bit and play with it some. I do have the throttle adjustment just off so the timing will advance some before it gets gas.

Are there any other suggestions? I feel as if i am C L O S E and it is wanting to RUN, but not there yet.

 

[CharlieB]

Re: 1985 Merc 115 in line 6

Most timing adjustments can be set cranking on the trailer. WOT timing, and the throttle pick-up point timing where the distributor turns that little bit and the throttle blades first begins to open. This should be at 4 -5 BTDC

Actual idle timing has to be set while on the water and in gear, this should be somewhere between 4 - 6 ATDC

If idle timing is set BTDC that may be part of the reason the motor stalls when rapidly backing the throttle off.

 

[rrumba]

Re: 1985 Merc 115 in line 6

Thanks CharlieB. Will check that today after work, after i get some gas :facepalm:

 

[rrumba]

Re: 1985 Merc 115 in line 6

Most timing adjustments can be set cranking on the trailer. WOT timing, and the throttle pick-up point timing where the distributor turns that little bit and the throttle blades first begins to open. This should be at 4 -5 BTDC

Actual idle timing has to be set while on the water and in gear, this should be somewhere between 4 - 6 ATDC

If idle timing is set BTDC that may be part of the reason the motor stalls when rapidly backing the throttle off.

Forgot to ask, if i am unable to get it to idle in gear how would you set timing in gear at idle?

I am going to try and do it once i come off slowly from a hole shot since it stills runs in gear but at idle there and hope that will work.

 

[rrumba]

Re: 1985 Merc 115 in line 6

had bad storms tonight so could not work on her.

another quick question to make sure I am not about to screw up again.

now that I have timing rough set. whe I take it back to the water tomorrow, should I readjust the timing for 5* after tdc?