Yep another "will not start" issues - 1973 18 hp Fastwin

[Sader762]

Sorry! I know this is one of the most common asked questions. I've spent two days on this on the computer and going over my manual for this motor. I'm stuck!!!



Bought a 1973 18 hp Fastwin for my Jon. It was a long shaft motor. Put it on and ran it a couple of times over summer than it stopped running on me. I wanted to make a Jack Plate to get it up some and redo the motor. In the mean time I ran my Jon boat with my 5.5 hp Fisherman which I completely overhauled a year ago.

I finally get around to doing everything this week.

I have replaced the following:
impellar
lower unit oil
converted to a short shaft, cleaned all lower parts
coils, condensor, spark plugs (J4C gapped at .030")
fuel lines
carb rebuild kit (cleaned and replaced float, bowl gasket, needle-seat and gasket assembly, screw plug gaske)
cleaned fuel pump
Cleaned and relubed all control tiller arm area

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Compression is at 118 on both cylinders
fuel pump seems good - I can blow on the in-side (big) but not on the out-side (small), with small gas line off carb when I pull the cord it does spurt a small amount of fuel out
I can pull the cord and motor does spins like normal just won't start
I have good spark on both cylinders - jumps a good gap
I can put gas in cylinders and get it to run for 2-3 seconds really well then stalls out
Gas container pump bulb is hard

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I think I understand motors to a small extent, afterall I know the difference between gas and water, oil and grease...

I just don't get what the problem could be. Any help is appreciated!!!!!

Thanks for reading.

 

[jmendoza]

Re: Yep another "will not start" issues - 1973 18 hp Fastwin

Clogged low speed jet, low speed needle not open enough, no fuel in float bowl...

 

[JDusza]

Re: Yep another "will not start" issues - 1973 18 hp Fastwin

Concur with jmendoza. Not getting fuel.
You'll have to go deeper into the carburetor. In the rebuild kit there are usually new welch plugs. These are for the access holes to the low speed jets. You may be able to clear the jets from inside the carburetor throat with very small diameter wire, but that is not always successful in the long run because junk can float around inside the machining and re-plug the jets. You can see the small holes of the jets inside the carburetor throat at the throttle butterfly. To do it right, remove the old welch plugs and clear the jets with a tool and air.
J

 

[Joe Reeves]

Re: Yep another "will not start" issues - 1973 18 hp Fastwin

The fact that you can put a small bit of fuel in the cylinders and get the engine to run for a short time spells "carburetor".

Re check your work, especially the brass high speed jet that is located in the bottom center portion of the float chamber. Clean that jet with a piece of single strand steel wire... solvent just doesn't do the cleaning job properly.

Make sure that the choke works as it should and that "all" fuel and air passageways in that carburetor are clean and clear.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

(Point Setting Of Magneto Models)
(J. Reeves)

Set the points as follows. Have the flywheel key aligned with the fiber rubbing portion of the ignition points. Adjust the gap so that a .020 gauge will pass thru but a .022 will not. Should there be any question of the points being dirty (touching the contact with your finger would cause them to be dirty), clean them with a small brush and acetone or lacquer thinner.

NOTE 1: Should the operating cam have a small portion on it with the word "SET" imprinted, align this portion with the fiber rubbing portion instead of the flywheel key.

NOTE 2: Should the cam have the word TOP imbossed on the top of it, that is a cam that could be installed upside down and this is simply telling you which side is up. It is not a position where one would set the points.

(Magneto & Driver Coil Alignment)
(J. Reeves)

To align the coils properly, have the metal vertical portion of the coil yokes aligned with the inside edge of the bevel that exists on the top portion of the aluminum seat upon which the coils sit. This creates the proper distance between the coils and the flywheel magnets. Faulty alignment creats friction and the yokes of the coils heat up, turn blue and expand.

 

[Sader762]

Re: Yep another "will not start" issues - 1973 18 hp Fastwin

Thanks for the help. I'll tear the carb all the way apart again and go over it with a fine tooth comb. I'll post back in a few days as a follow up to wrap up the thread.

Thanks!!

 

[1946Zephyr]

Re: Yep another "will not start" issues - 1973 18 hp Fastwin

One other trick you can try too. Remove the plug on the bottom of the carb, where the access is to the high speed oriface is and see if fuel runs out while you pump the primer. If it does, that will narrow down the problem to the low speed circuit. If it does not, then you most likely have a clog, between the fuel pump and the float needle assembly.

 

[Tim Frank]

Re: Yep another "will not start" issues - 1973 18 hp Fastwin

I'd vote for carb issue as well....but I notice that in your list of "what's been done" you don't mention points.
Did you at least clean and reset them?

 

[F_R]

Re: Yep another "will not start" issues - 1973 18 hp Fastwin

ALL of the gas has to go through the high speed orifice plug (jet). Even the fuel that is on it's way to the slow speed circuit. The problem is probably not in the low speed circuit, but the high speed jet. It has to be absolutely shiny bright CLEAN. I disagree on shoving wires and stuff through it though. It is a precision part and oversize is just as bad as undersize (clog). But to each his own.

 

[kfa4303]

Re: Yep another "will not start" issues - 1973 18 hp Fastwin

Ditto. I'm thinking Hi speed jet too. Here are some handy links. They aren't for your exact model, but the basic process is the same.

http://www.duckworksmagazine.com/07/columns/max/index1.htm

http://www.outboard-boat-motor-repa...hnson 5.5 HP 1954-1964 Carburetor Tune-UP.htm

 

[Sader762]

Re: Yep another "will not start" issues - 1973 18 hp Fastwin

Well, after pulling the carb apart 4 times I came back to some research and saw the other posts. I tried to get the main jet out of the float bowl but it would't budge. So I used the next best thing - 30 psi of compressed air! I blew everything out multiple times, cleaned her up, reassemled and reinstalled and she fired up!!! Yay for me!! Now I just need to get the carb adjusted so that it runs smooth and idles right.

Thanks for the help guys!!

 

[Joe Reeves]

Re: Yep another "will not start" issues - 1973 18 hp Fastwin

Carb adjustment.... #4 post above.