Evinrude 6HP 2- cycle question

[skipgundlach]

Evinrude 6HP 2- cycle question

Our engine isn't developing full power. We had not used it for some time, but the problem existed long before the layup.

Initially, it sounded like it was 4-cycling, with a bit of a rattle - perhaps like preignition.

I first changed the plugs. There was no change in behavior. Then I ran a dose of sea-foamed fuel through it, and there seems to be some improvement. Very infrequently, it will sound "right" - but usually it's overtones of one cylinder running properly, and the other mostly 4-cycling (if that's what's happening).

This is a 100/1 motor, but the dealer who sold it to us cautioned that it was critical not to exceed that, and the 50/1 fuel we use in our Johnson 15 would be fine. To simplify inventory/space, that's what we've done for very nearly all of the time we've owned it. If that's a contributor, I guess I could manage the different fuels.

Ideas?

Thanks.

L8R

Skip

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[Stu Jackson]

In electricity, 99% of all problems are the connections.

In outboards, 99% is the carb.

[skipgundlach]

Originally Posted by Stu Jackson

In electricity, 99% of all problems are the connections.

In outboards, 99% is the carb.

Would the carb be responsible for one cylinder not working well nearly all the time, and the other, mostly well?

OTOH, I just took apart my Honda 2000 carb and I was astounded at what came out of the bowl. I'm amazed that it even ran.

Thanks for thoughts.

L8R

Skip

[a64pilot]

I'd bet it is four cycling, that is of course just simply running rich.
My belief is clean the carb and stay with the 50 to 1 oil mix.
I've seen the enrichining circuit cause problems before, assuming it has one and not a simple choke.

[Stu Jackson]

Originally Posted by skipgundlach

Would the carb be responsible for one cylinder not working well nearly all the time, and the other, mostly well?

Skip, more info is always helpful.

On my 1971 VW Super Beetle - loved that car ex-wife made me sold it shoulda sold ex-wife first! - it turned out rough running was because the spark plug wires needed to be replaced.

Good luck.

[Yeti]

I have had an older Johnson/evinrude 2 cyl do similar things to the one cylinder running well and the other not. I tried similar things like cleaning up the carb and checking the spark plugs. It turned out to be a smaller ignition wire that had came unplugged for the missing cylinder that was well "up the line" from the spark plug . It was kinda on the back and underneath stuff a bit and was somewhat hard to find without digging around a little bit. Once identified it was plugged it back in and everything ran like a champ after that.

Also, here's a pretty good link for the older Johnson/Evinrude Outboards. lots of info here.

http://www.leeroysramblings.com/Outb...0articles.html

[ohdrinkboy]

I have an early 90's 8hp 2 cycle and my electric pack went out. Only 1 cyl would fire with the failure in the pack.

[Stu Jackson]

Nice link to Leroy.

This works, too:

Evinrude Parts & Johnson Outboard Parts at MarineEngine.com

[skipgundlach]

Thanks, all,

I'll do non-destructive electrical testing first (swap spark plug wires, leave one off when starting to see if it won't start, etc.), then dig into the carb if I haven't solved it.

I use only marine fuel aboard, certified alcohol free - and here in the Bahamas, there's none of that stupidness...

Others think rings for the rattle; I surely hope not, particularly with my double-oil ratio.

My bet is still on a reed, but I'll be doing non-destructive testing on electrical questions before getting out the wrenches.

I wonder if there's a PDF tutorial like there is for the Evinrude 6 like there is for the Honda 2000 carb...

[a64pilot]

Originally Posted by Stu Jackson

Skip, more info is always helpful.

On my 1971 VW Super Beetle - loved that car ex-wife made me sold it shoulda sold ex-wife first! - it turned out rough running was because the spark plug wires needed to be replaced.

Good luck.

71 was a good year in Bugland, first year of the dual port head if I remember correctly.
We had matching orange 71 Super Bug with 88 mm jugs making it an 1800 CC engine I think, and a stock orange 71 Westfalia campmobile.

But have you driven one lately? I did a few years back, actually horrible vehicles really, poor fuel mileage, noisy, hot, low power, no power anything.
But you could fix on with a pair of vise grips and a screwdriver

[a64pilot]

Often 2 cl two strokes only have one coil / ignition system, the plugs fire simultaneously every time a cylinder hits TDC, known as lost spark ignition, one plug is firing on TDC exhaust so nothing happens of course, could still be a bad wire or cap of course though.
I like "sparky" plug caps, that is honestly what their name is, cheap, essentially waterproof.
Sparky Plug Caps [91A] - $1.45 : Parts Reloaded, Your Source For Hard To Find Motorsports Parts

[skipgundlach]

Right. I think I may dimly know that lost spark is what we have, if not on this one then on the 15. I'll have a better idea after mucking around with it later today.

[Stu Jackson]

Originally Posted by a64pilot

71 was a good year in Bugland, first year of the dual port head if I remember correctly.
We had matching orange 71 Super Bug with 88 mm jugs making it an 1800 CC engine I think, and a stock orange 71 Westfalia campmobile.

But have you driven one lately? I did a few years back, actually horrible vehicles really, poor fuel mileage, noisy, hot, low power, no power anything.
But you could fix on with a pair of vise grips and a screwdriver

THREAD DRIFT - all my fault, Skip, sorry about that!

Anyway, a64, my understanding is that the new Bugs are only Golfs with a different body, so it's a completely different animal. Need to go to MX to find a REAL one!

[skipgundlach]

I wonder if the bug from MX is the same as we knew as kids, or some other incarnation with the same body/frame, etc...

[Cadence]

How old is the engine? I've had what sounds like similar problems with two older OMC's 9.9s.
They would not hold a point gap because of an worn upper main bearing. Had it with a 3Hp from a coil arcing to the underside of the fly wheel.


Ancient history but OBs of that size seem to stay around forever.