84 115 Tower of Power

[ZOUKeeper]

I'm new to the older outboard game, but I've already learned a lot...
I have the Tower of Power and I need some help. It coughs and shakes at idle, and when I put it in the water I couldn't throttle more than 1/3 without dieing and at 1/3 I was moving really slow.
So I put in new plugs and new fuel pump kit. It still coughs at idle and I'm about to try the water again tomorrow to see if the fuel pump kit was the fix for going slow. Beyond that, I'm not sure what else I can do, or if it's time to take it to a mech. Does anyone have any advice?

 

[Faztbullet]

A compression test and a spark check is what needs to be done first...

 

[ZOUKeeper]

I have 100 psi on all cylinders and all the plugs have good spark. The changed gaskets, diaphragm, screen, and orings to the fuel pump made it sound a little better. But on the water this morning I had the same issues. Throttle to 1/3 I was moving 2 mph or so, anymore and it dies, Idle sputters a little like the engine is slowing down too much or is about to die but then keeps cranking. I feel like I'm close... What should I try next? Thank you in advance y'all!!!

 

[Chris1956]

Have you done a link and synch? Did you change/adjust the idle mixture adjustment on each carb? Too lean of an idle mixture adjustment can cause it to die on acceleration.

 

[ZOUKeeper]

Chris1956 The flies open together on all three, same place/ same time. I tried messing with the idle screw on all three, but I didn't see a difference other than I killed it once. As crazy as it sounds, I'm hoping dirty carbs is the answer.
Full disclosure I'm pulling and rebuilding all three carbs tomorrow and Saturday, and I just learned how to set the idle screws after cleaning. If it doesn't work after this I'm really not sure where to go next...

 

[ZOUKeeper]

You guys are awesome man! Thanks for helping me out!

 

[ZOUKeeper]

Carbs are clean, new gaskets and all in. Idle screws are set and it sounds great. Only problem left is that at wot I'm maxing out at 3100 RPM... Is that a governor issue, or a throttle cable issue, or something else? If it's a governor thing how do I adjust that?
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[Chris1956]

Well, the motor does not have a governor. Have you inspected the spark plugs to make sure all are firing? they should all be the same color, lite to dark brown or black are acceptable. Real clean or grey is an issue.

With the cowling off and the motor off, push the throttle all the way forward. The carb throttle plates should be nearly wide open. If not, you have some sort of linkage issue or link and synch issue.

There is a throttle stop set screw that could be stopping the throttle from opening.

If that's not it, the max spark advance could be les than the recommended 21* BTDC. Do not adjust unless you are doing a link and synch.

Lastly, you could have a prop with too much pitch. What boat and what prop pitch.

 

[ZOUKeeper]

24 pontoon, 13 pitch

 

[racerone]

Do NOT run this motor until you determine the fault.----Say it is a blockage in one carburetor.----No fuel going into 2 cylinders means NO OIL either.

 

[ZOUKeeper]

Update...
Idles at 1000, no kicks... Like a champ.
Carbs soaked and gaskets replaced, super clean.
All new NGK plugs, one new pack, all sparking strong.
Fuel pump clean and all new gaskets.
All cylinders are between 100 and 102 psi.
No leaks in fuel line as far as I can tell.
Water pump replaced, all new everything... Pissing good.
Idle sets are purring at 2 1/2 turns out on all three.
Idle and Throttle set screws are set well. Flies all open wide at same time at WOT.
Exhaust system cleaned to the extreme.
Fuel system cleaned out with 32 gallons of 50:1 and two cans of seafoam.
Prop is 13 pitch pushing a 24' pontoon, I've been told by the prop shop that it should work perfectly.

At wide open I'm staying at 3000 RPMs and feels like between 10 and 15 MPH.
Every once in a while the RPMs will jump up to 4000 or even 5000 for a couple of seconds, but then it will die. Fires right back up no problem, then levels back off at 3000.

I'm about to throw in the towel because I'm not sure there is much more I can do. On the upside, the motor is running much better than the day a bought it. I feel like I'm close, Does anyone have any other suggestions to help me get this beast over 3000 RPMs?

Thanks no **** you guys! I appreciate all the help!

 

[Chris1956]

Did you inspect the spark plugs for fouling or water? It sounds like one of the cylinders is not always running.

 

[Faztbullet]

Check spark on all six as sound like stator is dropping a switchbox on high speed side

 

[ZOUKeeper]

So I did an ohms test on the stator. Battery and all six wires were disconnected.
Red lines- 298 together, and 140s to ground
Blue lines- OL together and OLs to ground
Yellow lines- .8 and screaming together, and OLs to ground

I think that means I have a bad stator? Does that mean I have to change the trigger plate too?

 

[jheron]

The stator on that motor is just to charge the battery if I am not mistaken.
Cheers,
Jon

 

[Chris1956]

Jon, the early 1979 and older inline sizes have battery driven ignition. On those the stator only charges the battery.

Newer inline six models have ADI ignition, powered by the stator.

ZOU, the CDIelectronics web site sill have an ignition test for your motor.

 

[Faztbullet]

Blue lines- OL together and OLs to ground

Your on track now....that is bad

 

[jheron]

Jon, the early 1979 and older inline sizes have battery driven ignition. On those the stator only charges the battery.

Newer inline six models have ADI ignition, powered by the stator.

Thanks for that!
I mistakenly thought they were the same right up until 89...
Cheers,
Jon

 

[ZOUKeeper]

So I literally just bought a new stator and checked the resistance and to ground on all the wires before installing, and I'm getting nearly identical readings on the new stator. What does that mean??? Did I just buy a bad stator, or did I already have a good stator?