Re: [OMC-Boats] carb question....bittersweet weekend outing

Dan: I have a 1967 155 Hp Johnson Reveler, but I'm not the one having the
trouble. These problems sure can be frustrating, but at least there's a
chance you can "see" what the problem is, not like modern electronic modules
where the little electrons could be doing anything (generally intermittently
and/or randomly) and you have no clue. I think it was Lee who commented
earlier how we've all been there, done that, when it comes to desperately
changing parts hoping to hit the problem. My turn for that was on my 1983
T-Bird. I routinely got 30 MPG on the highway -- over 600 miles per tank.
I'd literally leave Michigan and not stop until I crossed the Tennessee
border, 3 states and 600 miles away. (Hearty midwestern states, not those
New England postage stamp states -- good bladder control in those days too!)
I did this for years, then one day, overnight, it dropped to 20-22 MPG. I
rebuilt the carb. I replaced all my plug wires, plugs, coil, and just about
everything else. I had the engineer who did the development on the carb
rebuild it. I checked about everything there was to check, but I never did
figure it out. It ran the same (great), but the fuel economy just
collapsed. I know it wasn't my imagination or a math error calculating the
mileage because like I said, I left MI and didn't stop until I crossed into
TN. I think it had a 22 gal. fuel tank, so >600 miles traveled pretty
easily computes to ~30 MPG over multiple trips. Bottom line, if you've
rebuilt the carb and nothing seems wrong with it, that's probably not the
problem so don't waste your money unless you can get a refund if it doesn't
work. The nice thing about an internal combustion engine is it eventually
comes down to air, spark, fuel. Keep working those 3 and you'll eventually
figure it out. And don't underestimate the opportunity for bad fuel,
especially ethanol-based fuel that has a very short shelf life.

JD: I was going to ask before if you were sure your temp. guage was reading
accurately, but odds are with it stalling and giving what seem like accurate
readings later, that's probably not it. Still, it may be worth checking to
be sure -- the calibration could be off or set incorrectly. I kinda like
your last idea, though I'm thinking about taking it one step further and
setting it as a redundant guage. On the bright side, at least you got a
good day of boating in and hit trouble on the way back to the dock instead
of the way out. I'll be launching for the 1st time this w/e (work has been
brutal -- the negative side of being lucky enough to still be employed as an
automotive engineer). Hopefully I won't find any demons this year!

----- Original Message -----
From: "dan" <dbjt@...>
To: "Evinrude & Johnson Boats of the 1960's and 70's"
<omc-boats@...>
Sent: Monday, June 22, 2009 10:15 AM
Subject: Re: [OMC-Boats] carb question....bittersweet weekend outing

> andy... not sure what engine you have.....but i have exactly the same
> problem.... move the throttle slowly and I can get almost 30 MPH on the
> GPS...
>
> was thinking of replacing the carb altogether as i have cleaned and soaked
> it twice..............Dan...........spark arrestor ?????
>
>
> ----- Original Message -----
> From: "jd" <jdood@...>
> To: "Evinrude & Johnson Boats of the 1960's and 70's"
> <omc-boats@...>
> Sent: Sunday, June 21, 2009 10:38 PM
> Subject: Re: [OMC-Boats] carb question....bittersweet weekend outing
>
>
>> Thanks andy - marking starting points is a good idea.
>>
>> i'm still trying to see if i can pinpoint more what's going on before i
>> start twisting those screws. I had a interesting weekend with the
>> boat. Camped next to a huge lake. A huge lake that looked like a
>> miniature ocean, was very choppy and had about 2 other boats on it.
>> And there I was with a boat that I wasn't accelerating up to plane and
>> stalled out a few times when tested a few days before. But nothing
>> ventured nothing gained, right? First and foremost - it started right
>> up, and ran well enough to take family members out for short little
>> spins around in the whitecaps. Just getting to that point and being
>> out there zipping around was a huge milestone for me.
>>
>> As far as the carb/ running thing......I ran it the whole time without
>> the cowling on. It didn't completely fix things, but seemed to run a
>> bit better. So air supply is a partial problem and will be easily
>> fixed when I soon vent the cowling. (and clean the spark arrestor)
>> Next, fortunately the throttle didn't completely bog when I would just
>> move it slowly up in increments. I'd move it a little, take my hand
>> off, and then let the engine sort of "catch up" to where the throttle
>> was set, then move it some more, until eventually was cruising around
>> at almost full speed. And the best part is the temp was always holding
>> solid at 160-170. So FUN! My last boat was an '80 Glastron with
>> a Johnson 110 outboard, and this '64 Deluxe seems to be faster and
>> handle the chop a bit better - love that. So, even though it wasn't
>> running tip top, it was enough to get by with and I was on cloud nine.
>> Then of course doom had to strike. I was on my last run heading back
>> towards the dock (fortunately) at almost full throttle when it started to
>> sputter a little.........i instinctively glanced at the brand new temp
>> gauge and it was pegged (somewhere over 250). Yet water was flowing
>> through the hoses just fine. (I still have my clear hoses on from all
>> the previous testing). Immediately shut it down. Felt the
>> manifolds, top of water pump - things were hot, but nothing close to
>> 250 degrees. Waited 2-3 minutes and then started it back up and went
>> very slowly back to the ramp. It started right back up, nothing to
>> weird with the way it ran. So hopefully I didn't do any permanent
>> damage.
>>
>> So now I don't what is up. Turned the key on after it was cold, and
>> temp gauge reads 0. All wires still connected in back. Guess I'll
>> take it back out this week for some more testing and see if it climbs
>> right up to hot, or holds at 160 for awhile and then jumps up to hot.
>> No matter what, I am getting a temp gauge with a built in buzzer
>> warning.
>>
>>
>>
>>
>> On Jun 19, 2009, at 4:39 PM, Andy Perakes wrote:
>>
>>> Tuning a carb is more art than science. Since its already running bad,
>>> you won't hurt anything by messing with it. Its helpful if you keep
>>> track of the original positions in case you get too far off and need a
>>> "known running" spot to return to: It can be easy to lose count from
>>> where you started so I usually run it all the way down, keeping careful
>>> count of the turns. This gives you a reference point to work from. It
>>> can also be helpful to know how many turns until the needle pops out so
>>> it doesn't inadvertatently pop out unexpectedly and cause something to
>>> get lost. Pulling it out gives you the change to inspect for
>>> contamination, varnish build-up, etc. too. Just be careful you don't
>>> lose the darn things -- tie a string on them if you have to.
>>>
>>>
>>> ----- Original Message ----- From: "jd" <jdood@...>
>>> To: <rees4@...>
>>> Cc: "Evinrude & Johnson Boats of the 1960's and 70's"
>>> <omc-boats@...
>>> >
>>> Sent: Friday, June 19, 2009 6:14 PM
>>> Subject: Re: [OMC-Boats] carb question....
>>>
>>>
>>>> perfect - thanks! i'm printing this out and taking it with me out
>>>> there.
>>>>
>>>>
>>>> On Jun 19, 2009, at 1:30 PM, <rees4@...> wrote:
>>>>
>>>>> those are your idle mixture screws. i'm assuming you have a 1970 2
>>>>> bbl carb. if so screw each one in gently until they stop on the
>>>>> needle seat. back them both out 1 1/2 turns. this should get you
>>>>> close. run until your boat is fully warmed up then one screw at a
>>>>> time turn the screw to the right slowly till the engine just starts
>>>>> to hesitate and stall. next turn it to the left until the fuel
>>>>> mixture is rich and the engine starts to lope or run rough. then
>>>>> turn the screw to the right until engine runs smooth.all this is
>>>>> done at idle. hope this helps. if someone knows more i won't be
>>>>> offended if you chime in.
>>>>> ed
>>>>> ---- jd <jdood@...> wrote:
>>>>>> so no one knows and/or wants to take a crack at what the two
>>>>>> adjusting
>>>>>> screws under the carb actually do? would love to know......so i
>>>>>> don't make things worse by guessing my way through.
>>>>>>
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Received on Monday, 22 June 2009