1997 50HP Johnson J50PLEEA Consistent Miss at all speeds

[RHMinetti]

This two cylinder engine has a consistent miss at all speeds; changed plugs, gas, checked timing, had carbs rebuilt, etc. The idle speed timing is set at 1 degree BTDC and at 5000 rpm it is 19 degrees BTDC, just what the Johnson book indicates. The idle screws have to be set out about 4 1/2 turns for the engine to run at low speed at all and the exhaust smells of raw gas. And the idle speed is about 1100 RPM, but I can't get it to run slower, it stalls (book says it should be 800RPM - Tach could be wrong). The compression is 139PSI top cylinder and 138PSI bottom cylinder so the reeds are apparently okay. Blew out the fuel lines, etc.<br /><br />This engine has a solenoid unit on the right hand side near the throttle and shift linkages. I think it is the electric choke solenoid as I can hear it click when I push the ignition key in. At its base is a Schrader valve stem with a grey valve stem cap attached. Beneath the cap and attached to the valve stem is an orange plastic pointer assembly. At idle, when this pointer is rotated CCW to the stop, the engine stalls; when rotated CW to the other stop the engine speed increases and then decreases somewhat. It runs rough at the "best" or mid range setting. There is about 90 degrees of travel for this pointer, from stop to stop. Can anyone tell me what this is and how to set it? Could it control the high speed air/gas mixture?<br /><br />Thanks

 

[DJ]

Re: 1997 50HP Johnson J50PLEEA Consistent Miss at all speeds

RHM,<br /><br />For "running", the primer solonoid lever is supposed to pointed toward the body of the solonoid. Not away from it.<br /><br />4 1/2 (idle jet) turns out seems to be a bit rich, in my mind.

 

[jim dozier]

Re: 1997 50HP Johnson J50PLEEA Consistent Miss at all speeds

I'm with djohns on this. I don't have the book on this engine but 4 1/2 turns sound too far out. Perhaps it has been screwed out this far to compensate for a clogged jet, or perhaps you have an air leak, in which case it might not be running rich because of the clog. You said the carbs were rebuilt but were they rebuilt adequately? It certainly sounds like a fuel delivery problem with the carbs.

 

[OBJ]

Re: 1997 50HP Johnson J50PLEEA Consistent Miss at all speeds

Hi RHM.....<br /><br />The reeds will not effect the compression of the motor. However, they will effect the way the motor idles if broken or cracked. Idle the motor down as far as it will go and see if the carbs are blowing out instead of sucking in. Any blow back means the reed for that carb is damaged. Blow back will also cause a lot of fuel to be deposited at the front of the engine. Ditto on the above posts about the idle needle setting. Screw the needles all the way in until GENTLY seated then back out about a turn and a half and start from there for best idle if the reeds are OK. One more thing to look at, remove the primer tubes from the carbs and crank the engine without pushing in on the key to choke. Any gas coming from either tube means the solenoid valve is leaking throug as the engine is running and will need replaced. Good Luck and keep us posted.

 

[JB]

Re: 1997 50HP Johnson J50PLEEA Consistent Miss at all speeds

Something fishy about that engine, RH.<br /><br />Your model number indicates that it is a '99, not a '97.<br /><br />I think your engine is "4 cycling" from over-rich mixture. In 4 cycling the engine actually only fires on alternate compression strokes because of being flooded. Since you had to back the air bleed screws out so far to get it to run at all.<br /><br />Being that it is a '99, which was the worst year in the history of OMC quality control there could be something really spooky wrong with it. I read about a brand new '99 Johnson that had no needles in the carbs!! <br /><br />I would start with the carbs. Overhaul them and give particular attention to the float needles and the float level settings.<br /><br />Let us know what you find.

 

[ob]

Re: 1997 50HP Johnson J50PLEEA Consistent Miss at all speeds

Just one addition to the good help you are already recieving,The red lever on the side of the primer solenoid is a manual prime lever for cold startup ,in the event that your electric solenoid is inoperative.This lever should be in the fully closed position after initial startup.(inline with the primer body.)If you have to leave it open at all in order for engine to run smoother ,you most definately have a problem with fuel flow through your carburetors,as 4 1/2 turns open on your slow speed needles would indicate.<br /><br />Ditto on JBs 1999 model.EE in the model number depicts 1999.

 

[clanton]

Re: 1997 50HP Johnson J50PLEEA Consistent Miss at all speeds

Check the VRO pulse hose, behind the starter, starter rubs a hole in hose. Idle timming is 1 degree -+ 1 ATDC, not BTDC.

 

[RHMinetti]

Re: 1997 50HP Johnson J50PLEEA Consistent Miss at all speeds

Thanks to everyone that replied to my posting on the 1997-9 50 HP Johnson J50PLEEA.<br /><br />Will try all the above starting with the reed valve check first. Then the carbs, etc. <br /><br />However, no one has told me what the Schrader Valve is there for? What does it do? The orange pointer, which I now know is the cold start choke, is attached to that valve stem. It looks like the valve stem on an ordinary pneumatic tire auto wheel rim.

 

[ob]

Re: 1997 50HP Johnson J50PLEEA Consistent Miss at all speeds

It's for decarbing and fogging your cylinders.Your engine should idle around 1100 on the hose.About 1000 in the water ,and idle should be adjusted to run 850 in gear with boat unrestricted.However loopers don't idle in gear at 850 very smoothly for any length of time and will beg to be run at 1000 +.For idle speed adjustment,you should be able to achieve this by adjusting the trunion nut on the throttle cable counter clockwise(to increase idle) as looked at from inside the boat.

 

[OBJ]

Re: 1997 50HP Johnson J50PLEEA Consistent Miss at all speeds

RHM...<br /><br />You got a 99' there like JB said.