18 hp fastwin maiden voyage!!

JKTrevecca

Petty Officer 2nd Class
Joined
Sep 20, 2009
Messages
110
Many of you helped me after I purchased my boat last Wednesday to diagnose why it had run very well the day before I purchased it, yet wouldn't start for me after I got it home. Thank You!

Well... Last night was my maiden voyage...:D:D:D:eek:

Ran great. However.... at WOT, I would adjust the fast needle knob and it wouldn't stay where I wanted it to. I'd run for 30 seconds, notice I was bogging down, and look back to find the knob had turned to rich. This happenned 3 times and the third time, I couldn't get it to re-start.

I got it home, tightened the nuts at the end of the slow and fast speed adjustment knobs so they won't self adjust anymore. (packing nuts I think?)

Now... I am a little lost. It still won't start and continue running smooth like it did when I first took it out. I have read the carb adjustment tips from the top secret file and want to know if the 1 turn out and 1 1/2 turns out starting points are in reference to the exterior adjustment knobs??? If so... then I am a bit puzzled b/c the slow speed knob doesn't turn more than 1/2 turn before stopping in both directions. The high speed knob will turn counter-clockwise indefinately (i suppose... i stopped after 2-3 turns) and will eventually stop when turned clockwise.

Any thoughts on why I'm having trouble getting her running again? I imagine it is due to the carb having self adjusted itself and perhaps fouling the plugs... They were wet when removed.

If I start by replacing the plugs, can someone confirm for me if the carb adjustment procedure is referring to the exterior knobs or something under the hood?

Thanks!! Can't want to get back out. She ran GREAT as long as I kept the high speed knob stationary while cruising.
 

jdsgrog

Chief Petty Officer
Joined
Jun 19, 2007
Messages
480
Re: 18 hp fastwin maiden voyage!!

I had the problem with the needls on my '50's 18hp. For the knobs to fully turn, you need to either push in the front cover (there should be springs in back) or loosen the knobs and pull them out a little so they turn past the stops.

To adjust the needles, gently tighten the knobs/needles so they seat snugly and don't turn any more. From there, turn the low speed needle 1 1/2 turns out, and the high speed needle 3/4 turn out. That is your start point. Adjust according to directions. After adjustments are made, loosen the screws that hold the adjustment knobs in place; adjust them to about mid way, and then tighten them. That will give you a quarter turn for any fine tuning you need to do.
 

Elbo

Petty Officer 2nd Class
Joined
Sep 12, 2009
Messages
136
Re: 18 hp fastwin maiden voyage!!

I have a 63 mod.but it doesn't have the fast speed jet adjuster.On the newer ones ,there is a key way under the needle hole that takes a plastic grommet that will fit in that key way.That stops the self adjust prob.Packing washers also will stop the adjust prob.If that one does not use the plastic ones also.Those adjustment needles have to be set close to start with in order to use the knobs on the outside.Get the needles packed so they can't turn and get the high speed set and you shouldn't have to mess with it again.Set the low idle like the sticky says and go from there.You will only have a half turn to fine tune with.1/4 each way.Get that one first.You may have to take her for another run to get the fast one correct.
 

JKTrevecca

Petty Officer 2nd Class
Joined
Sep 20, 2009
Messages
110
Re: 18 hp fastwin maiden voyage!!

Those adjustment needles have to be set close to start with in order to use the knobs on the outside.

Does this mean that there is an adjustment on the carb other than that which can be changed by turning the knobs/shafts that are on the outside of the motor case?

Thanks for entertaining my rookie questions.
 

oldrudedude

Chief Petty Officer
Joined
Jul 3, 2008
Messages
480
Re: 18 hp fastwin maiden voyage!!

Yes! Take the cover off the motor and adjust the needles on the carb using jdsgrog's directions:

To adjust the needles, gently tighten the knobs/needles so they seat snugly and don't turn any more. From there, turn the low speed needle 1 1/2 turns out, and the high speed needle 3/4 turn out. That is your start point. Adjust according to directions. After adjustments are made, loosen the screws that hold the adjustment knobs in place; adjust them to about mid way, and then tighten them. That will give you a quarter turn for any fine tuning you need to do.

The knobs are for fine tuning while under way. They are limited in how far they turn. Adjust the needles on the carb first.
 

samo_ott

Vice Admiral
Joined
Jun 18, 2006
Messages
5,125
Re: 18 hp fastwin maiden voyage!!

I had the problem with the needls on my '50's 18hp. For the knobs to fully turn, you need to either push in the front cover (there should be springs in back) or loosen the knobs and pull them out a little so they turn past the stops.

To adjust the needles, gently tighten the knobs/needles so they seat snugly and don't turn any more. From there, turn the low speed needle 1 1/2 turns out, and the high speed needle 3/4 turn out. That is your start point. Adjust according to directions. After adjustments are made, loosen the screws that hold the adjustment knobs in place; adjust them to about mid way, and then tighten them. That will give you a quarter turn for any fine tuning you need to do.

This exactly right. There only are one low speed and one high speed adjustment. You either have to take the knobs off (tricky sometimes) or move the detent stops so that you can turn em all the way in and then out again.
 

14ftgrumman

Chief Petty Officer
Joined
Jul 19, 2008
Messages
416
Re: 18 hp fastwin maiden voyage!!

Remove the knobs from the front of the motor. Do the initial adjustment (starting point) per the sticky, when set as close as possible, replace the knobs.

You might have to replace the packing gaskets on the adj. screws, but it's not a big deal. Buy more than you need, as you will probably use them thru the years.
 
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