79 mercury inline 6 help

[3boydad]

Hello i have compression of 125 126 126 130 128 131. New plugs carbs rebuilt and fuel pump. It was losing power while wot caused by bad fuel pump. After my repairs on the water no issue at wot smooth sounds good and stays constant without issue. My problem is from idle giving throttle is seems sluggish and just doesn’t feel right. I have a new OEM trigger I was going to swap it due to the old one has the insulation crumbling off. When looking at flywheel and set at the black mark which is 1 degree the arrow seems to line up perfect with crank. Is that right? Anybody have experience with the Inlines and maybe can help me out figure out why I’m not getting smooth rpm for idle to wot? It idles great and wot is great. Thanks guys

 

[3boydad]

Oh yes, new fuel lines through motor new primer bulb. I think I can rule out fuel unless there is some adjustment I don’t know about. My carbs are all set at 1.5 from fully seated

 

[Chris1956]

Gee, a link and synch will assure timing is correct. I recommend you do that, as it will be a waste to blow up a fine motor.

Sluggishness during acceleration can easily be incorrectly adjusted carbs. 1-1/2 turns open is just the initial setting. It must be tuned on the water, warm and in gear. Normally the carbs will need to be opened a bit more, but trial and error is necessary to get it right.

 

[3boydad]

Thanks for your info. I have looked for link and sync and CS not seems to find that nor is it in the book. Can you point me to that?

 

[3boydad]

A mercury mechanic told me when tuning the air fuel on the set screw in carbs to make sure they are all set the same. That did not make sense to me either and it goes against the book but he said the book is wrong it can run lean if not all set the same

 

[racerone]

There are 3 carburetors.----Each carburetor supplies 2 cylinders.------A typical issue with these motors is carburetor slow speed needle adjusted to give the " best sounding " idle by ear.----But then there is not enuff fuel for the carry over to high speed metering circuit.-----Motor will stumble on acceleration.----So you need to open slow speed mixture 1/8 turn at a time till acceleration is smooth.

 

[3boydad]

Thank you for that info. The book states 1.5 from seated and turn in which I did so you’re thinking I need more fuel? I’m still replacing my trigger as I’m trying to get the nut off to remove the rotor and shaft without breaking it. Hopefully can be done without impact wrench

 

[racerone]

I am not " thinking " it needs more fuel.------On many occasions I have adjusted stumbling motors by adding more fuel.-----And it is a " no money spent " procedure for you to do !!

 

[3boydad]

Man if you’re right I will love you long time of course with social distance lol thank you for all this info the book sucks. I’m putting my trigger back together and of course the upper bearing got scored cause they tell you to pry it out. So ordered a new bearing but this old one still spins so I will put it back together like this and see how she does until bearing comes in. I can tear this motor apart in a matter of minutes now

 

[elr]

Have a 79’ 90hp as well. Just rebuilt and had It on the water today for the second time since rebuild. Was stumbling some on takeoff as well. Backed the carb mixture screws out a little and it cleared up. See link below. Still running extra oil and not WOT for long periods yet.

https://youtu.be/FxbU7TJ3SaM


racerone is an expert.

 

[3boydad]

Right on. It’s a great motor runs great minus the adjusting I need to try just as soon as I get my distributor back in.

 

[Chris1956]

If you have a service manual for that motor, and it doesn't have the link and synch procedure, it is only good for starting fires.

On a distributor inline 6 motor, idle pickup timing is 4-6* BTDC and max spark advance is 21* BTDC. You need a timing light in addition to a proper service manual to set it properly.

now that you are working on the distributor, a Link and Synch is an absolute necessity.

 

[3boydad]

Thanks for that info. There is updated notes for timing for our fuel we use now. However they never listed anything as link and sync. Just timing in general which to do it right it says find TDC to set the pointer. After that then setting the other adjustments. I just put it back together and it fired up very fast from a cold start. I did play with the air fuel on the carbs with muffs on. It’s so much better with the sluggish from idle to wot. And no I’m not running it wot with muffs just a quick zap to see how she behaves. I was considering putting her on the water today since I am 5 minutes from the ramp. May I ask why link and sync is critical after replacing trigger? The flywheel was put back on where I removed it at 0. And I rotated the arrow to point straight at the crank before slipping belt on. Which leads me to believe it’s right back where it was. I do want to check timing and I will I just wanted to know why after rebuilding distributor I need to do that?

 

[merc850]

You have to set the throttle pickup levers correctly; you can't set the low speed on muffs it must be done warm, in the water in Forward around 900-1000rpm

 

[3boydad]

Thank you for that I’m going to take it out Tuesday hopefully I can get this done solo

 

[3boydad]

Another question about these motors. Are they always a tad hard to start cold? It takes a couple cranks of 10 seconds or so before she lights off. Am I not giving Her enough gas maybe?

 

[racerone]

Outline your starting procedure at this time.-----Yes can be hard to start if you do not understand the workings of this motor at 40 years old.----Worn rings , labarynth seals, piston rings , warped choke plate on the upper 2 carburetors all add up.-------Next is to study how the wonderful electric primer used on many Johnson / Evinrudes motors works.------Was used on motors from 9.9 HP to 300 HP starting in 1980.-----I have installed that unit on a motor like yours and result was near instant starting !!!

 

[3boydad]

I think I was starting it wrong. I was squeezing bulb until hard. Then turn key on push in choke and start. But after searching and searching it appears I should prime it longer and raise the throttle lever about half way then push choke and crank. I’ll try that out. Where can a guy get one of those primers? I’m down!

 

[racerone]

Squeeze the bulb till very hard.-----Raise the fast idle all the way.----Be prepare to slow motor down immediately when it starts.-----Hold choke button in while cranking.-----As clearly stated those electric primers were used for many years , many different modes.----Used ones are everywhere.-----Dealers don't bother to take them off when I buy a parts motor.----They are the solution to hard starting on many motors.-----It could be installed on a 1960 model 18 / 20 HP motor whether it be Johnson or Mercury.

 

[3boydad]

I am looking to get one now you sold me on it. Kind of off topic question here. The top bolts on the flywheel not the main nut but the 8 that hold just the flywheel. Do you know the torque specs on those? Book clearly just gives the nut at 100 ft pounds. I know to loc tite those as well when I’m finished