1989 Evinrude 48HP SPL stalls at idle

[gmanzee]

I have a 48 hp rude on my pontoon - 50 : 1 premix. It was stalling at idle. Removed the two carbs and jetted the ports (gumout, fine wire, Comp air). Changed the gas. Primer bulb gets firm. Changed plugs. It always starts but I cant seem to get it to idle and have high end performance. My shop manual doesn't cover adjusting carbs much. I cant find the Top Secret file a lot of the post responses refer to. ...

 

[racerone]

A very common posting.------" cleaned the carburetors and still will not run properly "------I start the trouble shooting with a compression test.----What are the values on your motor ??

 

[Stumpalump]

Turn the carb screews out.

 

[oldboat1]

If your '89 has adjustment screws, start about three turns out from seated, unless you see a different instruction for your motor. I think older motors adjust a little differently, but principal is the same.

To get to the stickies, just click on the forum title up at the top ("Johnson & Evinrude Outboards"), then look for the stickies up at the top of all the threads -- "top secret" files. Can also do searches using the box up in the upper right (But don't reopen old threads by posting to them.)

 

[gmanzee]

Ok checked Compression - it was 135 in both cylinders - I think that rules comp out.
I'm now pulling carbs and going through clean, rebuild, adjust procedure again.
I have the link and Sync procedure - could do that?
Any other suggestions?

 

[juno pierrat]

remover core plugs, small holes under it need cleaning, there part of idle circuit

 

[gmanzee]

I removed the brass main jet and idle needle valve - used solvent and fine wire - then blew out with compressed air. Checked the op of the float with a hose blowing in when carb upside down it was sealed when rightside up it took air as it should. Now I can pretty much get it to idle on the water with it in gear when I advance the throttle it bogs at about 3/4's throttle.I have another gas tank primer bulb from another boat - swapped that in and does the same.
I just Cant find that happy spot where it idles and hits high RPM with power??

 

[gmanzee]

Thanks Juno !
Removing the core plugs and cleaning the three small holes underneath did the trick. I went back to the recommended three turns out on the Idle mixture screw also. Turned the key and it idled smoothly. On the water it went to full throttle and rpm smoothly.! I won't skip this step again! Lesson Learned!

 

[gmanzee]

SAGA Continues!
Starts up cold, idles good, ran at full throttle good. lower rpm to low and it stalls! and wont start back up!.
Starter cranks but its like its getting no spark
It did the same thing with a different gas tank and primer bulb? I've done the following this year:
Verified good compression - 135 each cylinder
Replaced fuel pump
New plugs
Rebuilt Carburetors
Cleaned gas tank and replaced gas
Should I replace Coil pack?
Any other suggestions?

 

[flyingscott]

Check for spark?

 

[gmanzee]

After a tow back to the dock I let it sit for an hour or so and was able to start it? Didn't run long as it stalled again ! Then wouldn't restart after running. So it has spark If only intermittently.
Put the cover on and walked away.
Dang Gremlins!

 

[oldboat1]

Spark test is done with an adjustable open-air tester, available at auto parts stores (cheap). You need to see a sharp half inch spark. Test with both plugs out, like you would have done with a compression test.

Have you done routine cooling system maintenance? Impeller and thermostat. Temp should be somewhere around 120 - 140F -- too cold or too hot (160F) and you can have issue like you describe.

Carb cleaning requires disassembly and soaking. The idle jet and high speed jet have to be squeaky clean.

 

[gmanzee]

Ok - will do on the spark test.
How do you check the cooling system temp? It has good water flow from the water pump.

 

[oldboat1]

top of the head. Old fashioned check is the heel of your hand -- should be able to hold you hand in place for a few seconds. Too hot to touch means it's running too hot.

An IR gun is good to have.

 

[jakedaawg]

Never mind, I see comp readings.