Mercury 115 Hard Start Fix

[Fiftybucks]

Hi all,
I have had extreme difficulty trying to start my '83 115. While crawling around the engine, I saw some words on the top of the cowling for a 'Manual Choke'. I have an electric choke, have tried it, and little or no results. Sooooo... I made a manual choke for my 115 out of a lid to a soap bucket and $3 of washers and locknuts.
here is the pic.


i made a video of the way it works here:
[video]http://s1328.photobucket.com/user/nomain/media/Mercury115_83/DSCN1879_zpsb66efd20.mp4.html[/video]

it worked and the engine started in 5 seconds... now runs bad... misses at almost all rpms.

here is a video of it running now with a bad miss at low idle
[video]http://s1328.photobucket.com/user/nomain/media/Mercury115_83/DSCN1881_zpscb9659be.mp4.html[/video]

i noticed quite a lot of fuel leaking onto a paper towel i had placed under carb #3. so...
Can I get Carburetor #3 off without taking off all three? so i can replace needle and seat.

 

[alldodge]

Re: Mercury 115 Hard Start Fix

Your saying prior to installing your manual choke plates the engine had trouble starting but once started ran great, and had no issues, correct? Now after the manual choke install it misses, runs bad at all rpms and is leaking fuel?

If all the above is true something was damaged, not installed correctly, or something else. Maybe the leaking carb number 3 but what changed?

 

[sam am I]

Re: Mercury 115 Hard Start Fix

I'm wondering if the enrichment valve (the solenoid looking thing in your video with the yellow wire w black strip) isn't/hasn't been giving you fits from the get go? The manual says......

"The enrichener system provides the engine with a
rich fuel charge for starting ease of a cold engine. The
system consists of an electrically operated enrichener
valve which is connected by hoses to the carburetors.
Fuel is gravity fed to the valve from the float bowl of
the top carburetor via a hose. When the key (or choke
button) is pushed in (and held in) current is sent to the
valve causing it to open, which allows fuel to pass
thru. The fuel passes thru a hose and is supplied to
the engine via fittings located on top of the middle and
bottom carburetors. When the key (or choke button)
is released, the valve will return to the closed position.
The valve can be operated manually if valve fails
to operate electrically, refer to ?Manual Operation of
Enrichener Valve,? following.

MANUAL OPERATION OF ENRICHENER VALVE
IMPORTANT: Use of enrichener if engine is warm
could result in engine flooding.

Squeeze primer bulb until bulb is firm. Press button
in on enrichener valve and hold approximately five
seconds. Release button. Start outboard."

Maybe the thing is stuck of something? The manual says to trouble shoot....

"Push key (or choke button) in.
Valve should click.......


No Click......
Check for battery voltage to yellow/black
wire at terminal block on engine when key
(or choke button) is pushed in.


Click......
Squeeze primer bulb until bulb is firm.
Remove hose from fitting on bottom of
enrichener valve. Place a container
under valve, then push key (or choke
button). Check for fuel flow from fitting.

Battery Voltage Indicated
Check for loose or corroded connection between yellow/black
wire and black wire (under same screw at terminal block).
Check that other black wire at terminal block is properly
grounded.
Repair connection(s) as necessary, then push key (or choke
button) in. If enrichment valve DOES NOT click, replace valve.

No Voltage Indicated
Check for open in yellow/black wire between
key switch (or choke button) and terminal
block.

Fuel Flow from Fitting
Valve is O.K. Check hoses and fittings from
valve to middle and bottom carburetors for
leads or obstructions.

No Fuel Flow from Fitting
Remove hose from top carburetor at valve. If
fuel flows from hose, replace valve. If not,
check hose and fitting for leaks or obstructions."

I think the words your read ("manual choke") were printed on the motor in the event the manufacture didn't install a enrichment valve.....they save money that way ya know.

Worst case, try a different costco brand?.....J/K, you'll find it with a lil help from these folks here, they're all pretty damn sharp with these merc's.

 

[Fiftybucks]

Re: Mercury 115 Hard Start Fix

to AllDodge and sam i am.... thanks for the input.. and i will test out that yellow w/black wire.
1... I never heard the engine run prior to the purchase, but the previous owner said it ran. well maybe that was a mistake. but for 750 for the boat, motor and trailer... i cannot complain. hopefully i can get it running without too much more investment. the guy at the local parts counter kind of directed me away from getting it running as it was past the 20 year window they will even work on, but they have all the part kits and impellers etc.
2... I like the manual choke because i can see it at work. and it worked and the engine started. I believe that the enrichment valve is working, perhaps marginally, but just for some reason.. perhaps the 25 degree weather, just isn't quite enough. I plan to replace my costco detergent lid manual choke with the factory manual choke as soon as possible. Also.. man this engine is thirsty in present condition.. 1 gallon of test fuel, with 4oz of seafoam, in perhaps 35 min at high idle. Maybe it is just sucking massive fuel thru the bad carbs.
3... ALL Carbs leaked when i first pumped fuel to the engine, but gradually #1 and #2, stopped leaking. #3, is terrible.

So.. I have good compression, good spark, perhaps good timing haven't checked (not sure how), it must be the carbs. The previous owner's mechanic said that ethenol damaged the airways in the carbs ????? is this possible? i never thought it could erode hard parts? PLEASE advise me, as i would not like to go thru rebuilding these carbs and end up in the same place.

 

[alldodge]

Re: Mercury 115 Hard Start Fix

ALL Carbs leaked when i first pumped fuel to the engine, but gradually #1 and #2, stopped leaking. #3, is terrible.

So.. I have good compression, good spark, perhaps good timing haven't checked (not sure how), it must be the carbs. The previous owner's mechanic said that ethenol damaged the airways in the carbs ????? is this possible? i never thought it could erode hard parts? PLEASE advise me, as i would not like to go thru rebuilding these carbs and end up in the same place.

Recommend since they all leaked at first all need to be rebuilt or replaced. The kit for each carb kit cost 17.00 on iboats
Carburetor Kit - Sierra - iboats

A rebuilt carb will run under 100 each. Ethanol fuels damage older fuel system gaskets and seals not the bodies. If your handy with removing, cleaning and installing a carb kit, I would suggest rebuilding all three first. The main thing in rebuilding a carb is getting it clean in all the tiny passages which cannot be seen. Use some good cleaner and air to blow out passages. Once you have stopped all the fuel leaks you should have a good running motor unless there is something else going on with the engine that we are not able to see. Is the engine worth putting 60 into to find out?

 

[Fiftybucks]

Re: Mercury 115 Hard Start Fix

yes... the engine and the satisfaction is worth a lot more than the price of the boat. ... i am looking out the window right now at the lake, I have good carb cleaner, air compressor, tools, and lots of patience.
here is the view I should be out there with my mercury.

 

[sam am I]

Re: Mercury 115 Hard Start Fix

You're welcome $50, we get pretty cold up here too. N. ID here.... The enrichment valve combined with good working card's etc allows these things to fire up in pretty cold weather.
I think I've ran/stated up in a low as around 15-20 degrees F here. I'm sure other folks have been in even colder weather......anyway, they may try to die but, you just kinda touch and go with enrichment with the throttle cracked open a smidgen. It tries to die 4 or 5 times but, they settle down pretty fast.
Personally, I think once you get those carb's and enrichment systems all up to snuff, you'd be fine without adding a manual choke. G.L. and btw......looks pretty dang cold out there on the lake....brrrrrrrrrrr.

 

[James R]

Re: Mercury 115 Hard Start Fix

A word on carb cleaning. Invest in a gallon can of Gunk Carb and Parts cleaner. Strip the carbs and soak the parts in the cleaner for at least thirty minutes. Carefully poke the jets with tiny steel wire or similar and re-soak. Rinse with fresh water and blow dry. Shoot carb cleaner through the holes and jets. Rebuild with new kits.
I take one extra step. I use my ultrasonic tank as well but I am just fussy I suppose. The Gunk product will do a good job.

 

[banshee owner]

Re: Mercury 115 Hard Start Fix

50$ I own a 1975 1150 mercury outboard very similar to yours. Mine is a great running engine and pushes the boat right along if carbs are you need to do then im pretty sure you will be pleased with it. I LOVE the nick name tower of power lol

you can see a pic in my signature in one of my first couple of posts.

What year is your engine if i can find my repair manual and you need a page i can scan and email or post it here if need be (if i can find it not sure if i left it at the lake or not)

Sorry my bad i see you said it was an 83 ill have to look and see if my manual goes that new

 

[Fiftybucks]

Re: Mercury 115 Hard Start Fix

Do the carbs come off in a set.. and if you do that, does it mess up the timing?

I am ordering 3 total carb rebuild kits. I also purchased a used manual choke setup. I have tested the yellow/w black wire and the enrichment valve is working, and it has a push button on the top of the valve. Maybe something is clogged inside the carburetors. I also found 3 older mkw - 18 set of 3... (mine are mkw - 40) matched carbs. i will try the older 18s if the 40s can't be re-built. Thanks all for the re-assurance. I do have a manual, but find the suggestions here much easier to follow.

 

[Silvertip]

Re: Mercury 115 Hard Start Fix

If the primer system is leaking, manual chokes, carb rebuilds and whatever else you plan will not solve the "uses lots of fuel" issue. Just because the primer solenoid actuates does not mean it is working properly. If must seal CLOSED when the key is NOT pushed in. If the valve is damaged or leaking, it will pass excess fuel to the engine.

 

[James R]

Re: Mercury 115 Hard Start Fix

If the fuel feed line to the enrichener valve is in good shape, with the motor running you can carefully pinch the line with a pair of pliers and see if the motor rpm changes. If it does then the valve is leaking.

 

[Fiftybucks]

Re: Mercury 115 Hard Start Fix

I will try the pliers to squeeze the enrichment system. I know it clicks.. I think it may be jammed in slightly open position. Again.. it was 1 gallon in 35 min at 1800 rpm, no load... just seems high. When i get the carbs rebuilt i will check again. Does taking all three carbs off as a unit destroy the timing? I have read some threads about 'link and sync' and will ask about that after i get the carbs done.

 

[Fiftybucks]

115 Carburetor Rebuild '83 MKW-40

115 Carburetor Rebuild '83 MKW-40

Hi all,
I have removed all thriee carburetors as a unit, and disconnected #3 (bottom) from the the rest. I have somewhat dis-assembled the carburetor, and there was a little debris in the bottom of the bowl. the needle look a little worn. the float seems ok but how do you tell?

so... in my previous thread, the following kit was recommended

Carburetor Kit - Sierra - iboats

1 - Should I get the kit that has everything that goes under those Gasoila (reddish sealant) screws?
that Gasoila is $30 and the more complete part kit is $30
2 - or just the gaskets needle and seat.

 

[James R]

Re: Mercury 115 Hard Start Fix

You can take them off as you wish. Whatever is the easiest for you. You will have to separate the carbs and remove any hoses to do the cleaning. Make notes on the positions of everything. This is a great time to replace the fuel hoses with hose that will not be eaten by Ethanol. Napa probably has the correct size hose. The carbs will have to be synchronized when you get them back on. No biggie.

 

[Fiftybucks]

Re: Mercury 115 Hard Start Fix

Carbs taken off and cleaned, needles and seats etc. Primer bulb now gets hard with no drips. I built a test barrel for the 115 out of a poly 55 gallon drum by laying it down and cutting an oval hole where the 23 inch lower unit fits. Once filled, it covers the lower unit nicely. I did this because of the weather, I can't have running water outside with the temperatures, plus I wanted to see how the engine ran and idled with the lower unit completely submerged, not on the muffs.
Here is the barrel

I cleaned off all the burs and rinse so they didn't go thru the water pump. I also hooked a hose to the tell tail, and ran it back into the barrel. I put a hose bib on the barrel so i could hook the hose and drain clear down the driveway into the gutter.

I started the engine by using the manual choke at the begining of this thread. The engine warmed up, and ran a little fast idle.. i turned down the carb idle screws while i had it in gear in the tub. The tack is at 900 rpm while in gear and idle speed. Out of gear and neutral is about 1300. Here is a vid of the engine running:
[video]http://s1328.photobucket.com/user/nomain/media/Mercury115_83/Barrel%20Run/DSCN18911_zpsb7279728.mp4.html[/video]

Seems to run evenly now... but has issues with stalling when going into forward. Restarts easily. It did, and did not want to rev up, but i gave it a little choke, and it did rev up. Bringing back to idle from 3000 it idled fine. I think the carbs are out of sync with the timing but not sure where to start.

 

[James R]

Re: Mercury 115 Hard Start Fix

We didn't determine what year and model motor you have as far as I remember. Anyway I think your carbs have adjustable idle jets. If you have a manual you can find out what the initial setting is and adjust the needles with the motor running to get the best idle. Idle speed is usually adjusted by a stop screw on the advance mechanism. I can help you more if I know what motor you have. Just '115' is not sufficient.