V4 115hp '79 sputters and dies.

[reagon]

I was getting my 1979 Johnson V4 115 hp back in shape for the summer a few weeks ago and had it running on muffs in the driveway when the sound of the engine noticeably changed and it died. I tried to crank it back up and it sputtered for 1 or 2 seconds, then died. I have worked on it every few days since and nothing has changed. I changed out gas tanks, fuel, fuel lines, fuel pump, rebuilt carbs twice, ran it while pumping the bulb, even connected the gas line directly to the carbs and manually pumped the fuel while I cranked. Nothing has changed. I have good compression and spark. When I crank it with the fuel line from the fuel pump disconnected, it pulses fuel out. When I pump the bulb with the fuel lines disconnected, fuel spurts out. When I spray fuel in the carbs or leave the choke on, it will run a second or two longer. When I pull the fuel lines apart and crank it, it will also run a few seconds longer. But it continues to act like it is starved for fuel. If I open the throttle even a little, it won't crank at all. Everything seems to point to a carb problem, but I swear they're clean. Also, what are the chances that both carbs have a clog? Wouldn't a couple of cylinders run if one of the carbs was stopped up? Thanks for any help.

 

[emdsapmgr]

Re: V4 115hp '79 sputters and dies.

Maybe the flywheel key sheared and the engine is out of time.

 

[kenmyfam]

Re: V4 115hp '79 sputters and dies.

+1 on the above

 

[reagon]

Re: V4 115hp '79 sputters and dies.

That's something I had 't thought of. Would I just take the flywheel off to check that?

 

[1NewBoatGuy]

Re: V4 115hp '79 sputters and dies.

Check your timing first before removing the flywheel.
Very easy test and it will help verify any movement with the flywheel.
To do this,
-Remove all of the spark plugs
-Ground them to the power head
-Push the start lever all the forward to the start position (do this to allow movement)
-Then advance the throttle lever forward until it hit's the WOT stop screw (this is the max advance adjustment screw)
-Attach a timing light to the #1 spark plug
-Aim at the Timing marker arrow near the flywheel
-Check that the timing is set correctly.
-You may have to verify TDC as well before checking Max advance timing.

Also go through and use the Timing procedure in the Top Secret Section, it is helpful. What I explained pretty much sums it up though.

Something else to look at might be the floats in the carbs. They may be held open causing a too rich mixture.

I currently have the same problem with my 1979 115hp. Odd but true, it dies at idle, runs well at higher speeds. I think the floats are stuck. Timing does not seem to fluctuate at all.

 

[reagon]

Re: V4 115hp '79 sputters and dies.

Thanks. I'll give that a try. It's weird to see my motor on someone else's boat.

 

[1NewBoatGuy]

Re: V4 115hp '79 sputters and dies.

Check your boat, it may be lighter on the back now...