Odd behavior from b71 Johnson 60

[RobCutlip]

" I took my boat to the lake y

" I took my boat to the lake yesterday (the first time in 2 yrs) and it started right up and idled great! It's a 'no wake' lake but I did try to throttle up for a second and the motor started to bog and would quit if I didn't back off. I went to the local repair shop to purchase rebuild parts for the carbs (3 cyl w/3 carbs). Last night I put in new needles/seats, gaskets, and cleaned everything with carb cleaner. I took out the jet in the bottom of the float bowls and sure enough they all had a little crud in them. I took the boat out today and again it fired right up. Today the idle was a little more erratic and after idling for 20-30 minutes, the motor really started acting crazy. It would jump from a rough 1200rpm to about 1800 rpm and then go back and forth several times. Today when I gave it throttle it would still bog, only this time I would 'tap' the choke switch and it would speed right up and smoothly. Also, with the boat in neutral, if I move the start lever(high idle)up the motor would rev up to about 5000rpms! I had to apply the choke to get it down or turn of the key.
The longer I was out the worse the boat ran. I have good spark on all 3 cylinders and I know the carbs are clean. What else could be causing this? Coil, stator, rectifier? I have no idea.

The motor is a 60hp by the way, model # 60-ESL71c. Thanks in advance. Rob "

 

[joereeves]

"Rob.... The fact that the eng

"Rob.... The fact that the engine straightens out and runs better when you tap the choke indicates that the carburetors are still fouled somewhat, or/and are not adjusted properly.

If you had poor spark, some sort of ignition problem, tapping the choke would not correct that problem.

I'd suggest that you take another look at those carbs. It doesn't take much of a restriction within them to drag the performance of the engine down.

If all is well, and you think that possibly the carbs are adjusted wrong, apply the following to each carburetor, one at a time, starting with the center carb. DO NOT try to adjust all three carbs a little at a time. DO ONE carb, then move on to the next carb. You may have to go back over them a second time just to tweak them to perfection.

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

Joe

"

 

[smiffypr]

" Sounds like fuel Supply.
Ge

" Sounds like fuel Supply.
Get someone to pump the fuel primer while you open the throttle. If this works, its probably the fuel pump thats duff.
Pumps with rubber diaphrams do fail after time.
Depending on the design, you may be able to replace just the diaphram.
Smiffy "

 

[Bill Hoevel]

Also make sure the carbs are

Also make sure the carbs are syncronized. My son cleaned the carbs on our 50 hp. twin and didn't get it back together right. If off enough it can cause stumbling and eratic idle.