smokey bathtub ring

[ziggy]

i got this....

a smokey bathtub ring around my boat. i wash it off. take it out once and get it again....

my plugs also show signs of cold fouling. , dry, black deposits, sooty. i'm using ngk br6fs plugs which i believe is the sub for ac mr43-t.

i also do a lot of slow cruising. 900-1500 rpm....

for cold fouled plugs, possible problems are. that i'm aware of...

-clogged fa.- cleaned recently, wasn't dirty. was cleaned pre season
-flooding carb.- nothing done
-sticky choke- took fa off and looked. was wide open after up to normal operating temp
-weak ign. - plug wires pretty new and don't look degraded, new plugs, new points, condeser, cap and rotor. dwell, 31*, timing 6* btdc...

that leaves the carb. i'm thinking about doing a rebuild..... think i'm on the right track?

oh, i got two 2gc's. the one on the bench is off a 72 165.... i think it's the same as my 75. if i rebuild one, that'd be the one. i have no issues that i'm aware of other than the smoke ring.....

 

[Bondo]

Re: smokey bathtub ring

Ayuh,....

I believe you're Right,.... That's Fuel....

 

[MikDee]

Re: smokey bathtub ring

Try one heat range hotter plug, bingo! as your engine gets older and more worn, plus a lot of slow speed running, both contribute to this problem. Don't you remember about carbon build up, if you don't take it to WOT once in awhile, to burn out the carbon. Or, if that's not the case, try one heat range hotter spark plug, as your engine gets older and more worn, plus a lot of slow speed running, both can contribute to this problem.

 

[ziggy]

Re: smokey bathtub ring

thanks guys for the input.
i think since i got the spare carb. i'm gonna rebuild it. if i fail at it, nothing lost as i ain't rebuilding the one on the boat.... any preference as to carb dip that ya like?

as for the hotter plugs. hum. i been thinking about it all night.
yer pretty good md. i don't do a lot of wot. maybe even not enough. certainly not every time i go out. do it once in a while to see if i still get wot spec. which i do. maybe even 4400. and i'd agree that ya pegged my slightly worn out L6 too... compression is only ok, certainly on the edge of spec. i think. one cyl. is a shade low and the spread is almost too wide. my concern for going hotter is it's against my better judgment. i was schooled that mfg. spec. something for a reason. if ya chg. it, ya probably chg. something else. i ain't sure i'm a mech. enough to know what the ramifications are. seems like pre ign. would be a possibility. and i'd rather clean smoke off than detonate.

i think my first attempt is gonna be at the carb. rebuild. ain't done one in a while anyways. so i obviously need some practice. + i got the spare carb. so i can't mess up anything i can't put back to the way it is now. as for the carbon buildup. i think i'll try to do a wot run more often. them L6's sure do wind up tight at 4400 though. maybe i should try the old school method of misting some water down the carb. to see if i can get any of the carbon buildup to go away too.

well. that's my plan at this point. carb kit on order. i'll see how that goes. if i get no relief from my problem. then i'll consider going to hotter plugs... it may well be the answer for the low speed running i do..... but i'm gonna try and keep it in spec. 1st......

thankyou......

 

[MikDee]

Re: smokey bathtub ring

One heat range hotter, is not gonna make a whole lot of difference in stressing your engine, and I doubt that will even keep them, from getting carboned up some, but the span maybe enough to take you through the season. Your old engine may even expand a bit, & run better Especially if you do alot of trolling, that's what surface gap plugs were designed for yrs ago.
Being a Gearhead for 50yrs, this is a trick I learned yrs ago on my old 1962 40hp bigtwin Evinrude, because it was a 2cycle motor, a few of my friends were using the hotter J6 Champions, instead of the stock J4's, so I tried it and found, it started better (less hand cranking for me, especially when cold, non electric start ) less fouling, and, an overall increase in power, & smoother running. Nowadays, if I have any issues with plug fouling, I go to the next hotter plug, and see if it helps. Of course on 2cycles this is more the rule, the the exception, I don't remember the number plug offhand, but I did this on my Yammie Waveventure, because that thing just drips excess oil into the flame arrestor that they call "Advanced oil injection" and has a tendency to foul the stock plugs. If you're using MR43T's that's a great plug, it is plated for corrosion I believe, and has a huge round center electrode, for beefy spark, compared to it's puny automotive equivalent, But, it is on the cold side, it's fine if you're out ripping up the water, but not made for constant trolling. Shoot, I remember in the 60's the track guys were using Champion J12's in there small block Chevys racing at Islip Speedway Drags, I don't know how they could do that, and keep their engines together? The stock plugs were Champion J6's, but I used J8's street, or track, in my 327/300hp 62' Impala SS 4spd with no problem. But that's my opinion, take it or leave it it's all ancient history now, do what you like, Good Luck Mike