1979 115HP Dies at Idle?

[1NewBoatGuy]

Ok so my motor is idling real rough and dying. At first I thought I screwed something up with the linkages when I replaced the fuel lines (they were leaking - spraying fuel, carbs had to be removed to replace them). Then I found one of the heads never heat up so I replaced the thermostats (now they heat up to about 140 on each cylinder).
So I went to the manual..
The manual is kind of tough to understand because it spans over so many different models and years of motors.
So what I did is I pulled off the air silencer cover so I could see the movement of the butterflys.
What I found is everything is soaked in fuel. The butterflys, the carb bodies, even the silencer cover it self is dripping.

What I think is happening is the float valves are not seating right. The motor also seems to be running pretty rich since the spark plugs seem oily or blackened when I pull them out.

Does this make sense why I cant get the motor to idle correctly or at all for the matter?
At start speed (a little past throttle pickup) it seems Ok, a little rough though at warm up (about 1100 RPM right at throttle pickup) Seems like it's backfiring at idle.
I checked the timing and it is right at 24 degrees cranking speeds at max advance. Max advance at WOT is 28.
compression is all over 120psi at each cylinder as well.
Just trying to provide as much info as I have.

 

[Joe Reeves]

Re: 1979 115HP Fuel Dripping From Carbs?

Re: 1979 115HP Fuel Dripping From Carbs?

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

 

[1NewBoatGuy]

Re: 1979 115HP Fuel Dripping From Carbs?

Re: 1979 115HP Fuel Dripping From Carbs?

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

Thanks,
This just confirms my suspicions. Im gonna pull the carbs tonight and check them out. I ordered a set of rebuilt carbs from a local guy and should get them this weekend. His rebuilt carbs cost me just as much as new jets & rebuild kits. So I figured I'd give them a shot.
Anyway, I digress... Thanks again

 

[1NewBoatGuy]

Re: 1979 115HP Fuel Dripping From Carbs?

Re: 1979 115HP Fuel Dripping From Carbs?

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

OK, last night I installed two newly rebuilt carbs but I am not noticing any change what so ever. I can not get the motor to idle. It will stay running but rough at about 1100 rpm. Still have fuel collecting in the silencer cover.
I got an appointment tomorrow with the boat mechanic but really want to avoid this.
Any other ideas?

 

[itsaboattime]

Re: 1979 115HP Fuel Dripping From Carbs?

Re: 1979 115HP Fuel Dripping From Carbs?

My nest step would be to check spark. It may not be strong enough and flooding itself out.
Just checking it with the plugs grounded isn't enough. It needs to be tested with a tester.

 

[1NewBoatGuy]

Re: 1979 115HP Fuel Dripping From Carbs?

Re: 1979 115HP Fuel Dripping From Carbs?

My nest step would be to check spark. It may not be strong enough and flooding itself out.
Just checking it with the plugs grounded isn't enough. It needs to be tested with a tester.

I feel like I'm just throwing darts now, off to the boat doctor it went this morning. Will know for sure with in a few days.

 

[1NewBoatGuy]

Re: 1979 115HP Fuel Dripping From Carbs?

Re: 1979 115HP Fuel Dripping From Carbs?

Ok got it back today, the boat mechanic found that there are poor connections at the spark plug wires to the plugs themselves. This I suspected and this I was able to verify. He also suspects fuel leaking from the crank case?! is this possible, a fuel leak from the crank case?
Said he sprayed wd-40 around the crank case while running and that is when it would quit.
i tried the same thing after tightening the springs in the spark plug wires and couldn't get it to quit. Nor did I see any fuel spray or leak from the crank case. this is obviously a major repair if the seal on the crank case is bad. But is this a likely cause for an idling problem?

 

[1NewBoatGuy]

Re: 1979 115HP Fuel Dripping From Carbs?

Re: 1979 115HP Fuel Dripping From Carbs?

The answer to my above question is, yes it is possible. After looking at a parts manual the crank case is actually a part of the intake system. So if the seal is indeed leaky, this may cause it to run lean since it would be drawing too much air.
Referenced parts manual Picture
http://www.marineengine.com/parts/evinrude-johnson-parts-diagrams/JOHNSON/43648.gif

 

[1NewBoatGuy]

Re: 1979 115HP Fuel Dripping From Carbs?

Re: 1979 115HP Fuel Dripping From Carbs?

So my next question is,
Has anyone removed the crank case cover with out removing the power head? Is this possible?

 

[Joe Reeves]

Re: 1979 115HP Fuel Dripping From Carbs?

Re: 1979 115HP Fuel Dripping From Carbs?

If you're asking if the crankcase can be split without removing the powerhead..... No!

 

[1NewBoatGuy]

Re: 1979 115HP Dies at Idle?

as I assumed, damn. I thought maybe there was some crazy way of doing this.

 

[1NewBoatGuy]

Re: 1979 115HP Dies at Idle?

Ok, well the crank case is not leaking. I could not find any evidence of this today while on the lake. I don't think anyway.
I had it out for a few hours giving it a good test of will.
And I have to say I am pretty impressed with this 30 year old boat.
It hit 58 mph according to my sons GPS, at about 5600 rpm at WOT. I have to say, that is spot on for this boat. I would be willing to bet when new top speed wasn't too much more.

After talking with a local boat mechanic the carbs I received were not rebuilt. The color of the gaskets gives them away.
Rebuilt carbs for this Johnson anyway should have a brown or tan gasket which indicates it is using the newer gaskets designed to handle ethanol gas. The carbs I thought were rebuilt has the old black gaskets.
So anyway, old carbs back on and no problems with excess fuel dripping or other problems (this problem was indeed a fludding problem due to ignition problems and idle being set way to low). Idle in neutral not in gear with muffs is set to about 1400 rpm. While in gear in the lake it drops to about 800. This I may dial down a little since when landing the boat it comes in a little fast.
Not trying to gloat here, just ending a thread with the results of a lot of elbow grease and good diagnosing has lead to.

My nest step would be to check spark. It may not be strong enough and flooding itself out.
Just checking it with the plugs grounded isn't enough. It needs to be tested with a tester.

Thanks for the tip, this really lead to good things by double and triple checking. Using a tester however did not yield accurate result. Using an inductive timing on each wire solved the problem (along with a little more knowledge of how to set idle speed).