What is left to try? Video link included! Help!

Joined
Jul 22, 2012
Messages
2
http://www.youtube.com/watch?v=YSxj3rsIeq4&feature=channel&list=UL

Ok, this link takes you to the last video I took of the motor running. There is one made prior to this that you can also see. This is what we have tried so far:

Since the last video we have replaced:
Spark plugs (NGK BZ7HS) Checked spark with spark tester, getting spark)
Coils (both)
Power pack
Fuel Line
We rebuilt the Carb
Checked compression. 120 each side
So NOW what? This motor is running the SAME AS BEFORE even after all of this.

Any helpers out there got any fantastic ideas? Woulod like to get this running asap so we can enjoy it some this summer yet!
Thanks!
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: What is left to try? Video link included! Help!

1978 35hp Johnson - What I see is someone risking having his finger torn off by playing with the spark advance (armature plate) while opening and closing the throttle butterfly. No offense but this really doesn't tell us anything. I assume that the problem is that the engine will not stay running. Champion QL77JC4 plugs, gapped at .040 or .030 is preferred.

Since the engine does run after a fashion, it's obvious that the flywheel key is not sheared.

If the engine has compression (approx 100+ psi and even on both cylinders), and a strong wide blue spark that will jump a 7/16" gap, then the problem would have to be either adjustments or a fuel problem.

If pumping the fuel primer bulb (acting as a manual fuel pump) corrects the problem, then suspect a failing fuel pump.

Adjustments:

Cam Roller: Adjust the armature plate cam so that the carburetor roller is dead center of the two marks on the cam when the throttle butterfly just starts to open. You do not want the throttle butterfly to open before or after it is aligned between those two marks.

Throttle Advance Rod (rod from vertical throttle arm to roller): With the engine NOT running, spin the propeller and put the engine into forward gear. Advance the throttle tiller arm or throttle control so that the armature plate is at the full spark advance position. Now, loosen the screw in the adjustment collar that you see on the rod, then with your finger slide that rod until the throttle butterfly is horizontal, flat, wide open, full throttle. Tighten the set screw so that the throttle butterfly will return to that setting each time the armature plate is turned to the full spark advance position.

With the above being as it should be, the engine should run UNLESS something has been overlooked within the carburetor.
 
Joined
Jul 22, 2012
Messages
2
Re: What is left to try? Video link included! Help!

Thanks for the reply, we will give those suggestions a go. Here is a link to the first video, the one we took BEFORE we did all those things previously mentioned.
Here is the link, longer and more detailed..
http://www.youtube.com/watch?v=oOzBcFmShgU&feature=channel&list=UL


Appreciate all the help and input! We are stumped over this and have never worked on a small engine before.
 

allmuckmojo

Seaman Apprentice
Joined
Jun 17, 2011
Messages
38
Re: What is left to try? Video link included! Help!

Im having this same issue. Ive done everything you have done plus a few other things. . . I readjusted the lowspeed needle black knob on the top of the carb, I checked the primer bulb to be sure it wasnt a fuel pumping issue. Im to the point to where I need to fix one of the adjustments I think. It will stay running now when i turn the choke off. but im still having issues. Im going to try what Joe Reeves has suggested. Were you able to give it a shot?
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: What is left to try? Video link included! Help!

Put the gas tank in the boat once and see what happens.
 

Haffiman

Commander
Joined
Dec 17, 2009
Messages
2,454
Re: What is left to try? Video link included! Help!

I'm missing the 'shading tree' in the videos, all I see (part of) is the mech!
Throw the muffs and get the engine in a barrel with water level min 2" above the split between leg and gear case.
Is engine getting up to operating temp? If not, change thermostat. Cold engine will not run!
Thermostat working??
Stop playing with the carb, it gives nothing but noise and may hurt the engine.
Loosen the screw for carb roller, set the mix screw 3 turns out.
Advance the timing, use the idle stop screw or remote.
Start the engine, and lower the timing advance to lowest possible rpm.
If engine will not run at a almost stable rpm only by advancing timing, pull down the carb!!
Clean all passages with a spray can of carb cleaner.
When putting carb bowl back, hold the carb up-side down, put on the small center gasket and the outer gasket and put the bowl loose on. The bowl should ride on the small center gasket and have a gap to the outer gasket!! If not, change the center gasket.
Report back when you manage to make the engine stable just by using timing advance and NOT opening the carb butterfly!!
 
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