Black Mudd? 40hp Johnson

[tiller7104]

I fired up my 40 this year and I am getting black mudd from my prop exhaust, not a little alot. I ran it on the hose for about 20 minutes and I had a puddle a foot around and about 1/2 thick on the ground. I am assuming this is unburned oil/fuel. I need to back up a minute I also eliminated my VRO this year. I am wondering if it is pumping to much fuel? I am running brand new 50:1 fuel that I know is mixed correct. Any ideas? Thanks in advance

 

[roscoe]

Re: Black Mudd? 40hp Johnson

Is this the motor you just picked up?<br /><br />I would replace the thermostat.<br /><br />Then do a good thorough decarb of the motor.<br />Will help the running of the motor, and will flush lots of that crud out of the exhaust leg.<br /><br />I picked up a 1990 40 Evinrude a couple years ago, and I haven't even started to put it together yet.

 

[tashasdaddy]

Re: Black Mudd? 40hp Johnson

keep your post in one place, it gets confusing, and we will get all the history.

 

[marysboats]

Re: Black Mudd? 40hp Johnson

If BRP still makes it, get the carbon guard that you add to the fuel. It sound's like you will want to check the RPM's on this engine, it sound's like you have a lot of carbon build-up.

 

[tiller7104]

Re: Black Mudd? 40hp Johnson

I did just pick this engine up.Is it possible that when I switched from VRO to hand mix that it is getting too much fuel? I know they are not a fuel efficaite engine but man there is alot of sludge. I am going to replace the thermo, to try and get it running a little hotter. It seems and runns as if it is loading up but the plugs do not looked fowled....I am thinking it is running to cold, I will do these sugestions and update you later Thanks Roscoe, good to hear from you! I am sorry abouth the multiple post but I figured they were to unrelated items...but now I believe they are one.

 

[marysboats]

Re: Black Mudd? 40hp Johnson

That sludge is carbon build-up. You need to get that engine up in it's operating range. You don't say what year your engine is, but go to the top of the range with average load. My experience has been that the 40 is under powered for the boat they are pushing. What boat do you have, and what is the horse power rating?

 

[tiller7104]

Re: Black Mudd? 40hp Johnson

Sorry great point. I have a 1990 40hp VRO it is on a 17.5 foot Sea Nymph Sportfisher. I am satisfied with te speed and hole power that is has when it runs right. I ordered a thermostat for it yesterday and I think that is a big part of the problem, it just runs way to cold. I hope to have an update soon any more possibilities please let me know. I have tried all of your suggestions with great results. Thanks again

 

[tiller7104]

Re: Black Mudd? 40hp Johnson

Update.....Thermostat in and what a difference. Well thanks for all the imput another world crisis resolved! Happy Fishing! Safe Boating!

 

[tiller7104]

Re: Black Mudd? 40hp Johnson

Update.....Thermostat in and what a difference. Well thanks for all the imput another world crisis resolved! Happy Fishing! Safe Boating!