Dirty Cyls 73 20 hp johnson

[chiefcatchemall]

Re: Dirty Cyls 73 20 hp johnson

okay guys thanks

 

[chiefcatchemall]

Re: Dirty Cyls 73 20 hp johnson

I noticed when I rebuilt the carb the kit came with a slow speed needle bearing...however when I went to install it, the slow speed needle wouldnt seat properly with this little plastic "bearing" in. So I ditched the bearing and just screwed the slow speed needle back in without it. Would this make a difference at all? I did not notice one in there before I rebuilt the carb so I am assuming its not a big deal... The part I am referring to is part #35 in the picture below...



http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1973&hp=20&model=20R73A&manufacturer=Johnson&section=Carburetor

 

[itsaboattime]

Re: Dirty Cyls 73 20 hp johnson

Sounds like it's flooding. The plugs may have enough spark but there may be too much fuel hitting the cylinders to burn it all and she runs rough and dies.
I would pull the head and clean everything and inspect the cylinders. Eliminate the concern the OP had in the first place. Then I would work on the spark/fuel issue.
Chief recheck you carb rebuild. Make sure your float seats correctly, the low speed needle is 1 1/2 turns out, and go from there.

 

[chiefcatchemall]

Re: Dirty Cyls 73 20 hp johnson

float sets parallel with the bottom of the float bowl...Next thing I am going to try is leaving the valve on the gas tank open, setting my low speed needle 1 1/2 turns out, and trying to find the exact plugs they call for...As of right now I am waiting on a fuel pump rebuild kit and the two coils that set on the outside of the motor...

 

[steelespike]

Re: Dirty Cyls 73 20 hp johnson

float sets parallel with the bottom of the float bowl...Next thing I am going to try is leaving the valve
When you squeeze the primer bulb it should get firm and not allow further squeezing.Normal for the bulb ro be lass firm as you use fuel.
on the gas tank open, setting my low speed needle 1 1/2 turns out, and trying to find the exact plugs they call for...As of right now I am waiting on a fuel pump rebuild kit and the two coils that set on the outside of the motor...

" Valve on the tank"? are you refering to the vent screw ? that should be open when you run the motor.
Have you tried unhooking the gas line when starting? Prime the carb and unhook the line,see if it will start.
As far as starting; any non resistor plug with the right reach would start it.The J4C will work fine.And champion are suggested.

 

[chiefcatchemall]

Re: Dirty Cyls 73 20 hp johnson

" Valve on the tank"? are you refering to the vent screw ? that should be open when you run the motor.
Have you tried unhooking the gas line when starting? Prime the carb and unhook the line,see if it will start.
As far as starting; any non resistor plug with the right reach would start it.The J4C will work fine.And champion are suggested.

I dont see a vent screw on the cap of my tank...Now when I start it the cap needs to be on tight correct? It has 2 positions on it. When its tight its vacuumed but when I back of it a quarter turn it releases all the pressure the tank builds.... then if I back the cap off another quarter of a turn the cap is ready to come off...Its an older tank...

 

[Brokeback Johnson]

Re: Dirty Cyls 73 20 hp johnson

A faulty fuel pump can cause flooding....been down that road it sounds familiar.

 

[BonairII]

Re: Dirty Cyls 73 20 hp johnson

When its tight its vacuumed but when I back of it a quarter turn it releases all the pressure the tank builds.... then if I back the cap off another quarter of a turn the cap is ready to come off...Its an older tank...

All you need to do is make sure that air is allowed to enter the fuel tank to there is no vacuum. The pickup tube is submerged so air isn't going to enter the fuel line(unless fuel level is low and sloshing around.

If you are suspect of the tank, just spend the $30-40 bucks and get a new one to save the you the hassle of it malfunctioning sometime in the future.

To take the fuel tank out of the equation, you can just run the bare fuel line into a regular gas can full of premix.

If it were me, I'd temporarily hook up a piece of clear fuel line($3 bucks) from the fuel pump and carb. You'll be able to if there's any air entering the system while the motor is running. I just did the same thing to my motor and found out that my carb was being fed a TON of air bubbles from a leak somewhere.

Just a piece of advice based on my limited experience:
Change out ALL inexpensive basic parts that are suspect on a new(to you) motor. Points, condensers, old looking plug wires, rebuild fuel pump, t-stat, old fuel line and connections.
Had I done that instead of doing it piecemeal on my motor, I would have saved a lot of headache.

 

[chiefcatchemall]

Re: Dirty Cyls 73 20 hp johnson

good stuff guys. Waiting on my fuel pump rebuild, and two new exterior coils. Also ordered a new kill switch and all connections as it was looking pretty screwy...