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Here is the scenario and what I have checked so far .

late Model atomic 4 , No EI , no electric fuel pump and raw water cooled , this is my 2nd year with boat and the prior owners were real purists.

last night on the way back to the mooring , the motor just stopped and a local fisherman towed us the last 50 feet ..

We had been motoring for about one hour , when the engine just died .. not run out of gas like the lawn tractor ,but just died ..I went to the boat this morning thinking that the coil was bad and after cooling all night it would fire right up and I would call Ken and order new coil, bobs your uncle problem solved .( As I have read in so many posts on this forum )

Nope not to be ... I closed the raw water intake tried to crank nut it wouldn't start .

I removed the cable from the top of the distributor and the coil produced a nice .25 inch spark .

I also removed the sediment bowl , it was full of gas to the brim and had some bits of sediment on the bottom .. as the fuel pump is mechanical how do you prime it ( the prime handle moves so little and I was afraid to force it )

My plan for tomorrow is to go to the boat with starting fluid and see if it runs
on ether momentarily.. which would be indicative of a fuel line issue ?


The engine has performed flawlessly for me and we where planning a cruise next week .. but not now ..

Sudden stop with good spark and some gunk in the sediment bowl: I would be looking for carb issues. If the priming lever is hard to move, the fuel pressure may be fine (note, I have an electric pump so am guessing here). Do you have an inline "polishing" filter between pump and carb? Do you have an inline fuel pressure gauge? I would suggest installing both those things when you reassemble your carb. And I would also suggest EI once you have it running again.

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Polishing filter is in place , in fuel pressure gage is not .. but will be installed

goodolboat, checking the spark at the time of failure is a must. As it topped suddenly it could still be electrical in nature~~don't forget to check the ignition for voltage from the Ign switch. The switch can get intermittent and drive you nuts. It can be checked with a meter or when she fails run wire from a HOT+ feed (battery a good place or the starter feed and take it to the coil + and see if she starts.

With your sediment issues a check of the carb is in order.

Dave Neptune

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Just to ad some further detail to this post ... just to give as many details as possible ..

The starter will crank strong and turn the engine over .. just wont start ..

goodolboat, did you try "motor crack" (starting fluid). A quick spray and a crank will let you know if you have spark at the plugs. If it kicks on "crack" you definitely have a fuel problem.

Dave Neptune :cool:

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Yes was going with some starting either today , if that gets it started .

I'm thinking fuel line ... if she starts on starting fluid does that preclude

a carb issue ? I spray into the flame arrestor that's the only air intake available ?
while on that subject does that ever need cleaning or maintenance ?

My 'would crank, had spark, but would not start issue' was solved by correctly adjusting the points.
Instead of the points gap being .2 as per spec, it was way out at .5.
Visibly you would see spark, but it was not blue and strong.
Was not enough to actually fire when the plug was in the cylinder.

If it starts or sputters on crack that means the ignition side is functioning. It also means that the carb is not delivering fuel properly.

The flame arrestor does need inspection and occasional cleaning.

When the engine quit did it shut down like you turned off the ignition or loose power, run a bit rough and die in a few seconds?

Did you check the carb bowl for fuel after shut down? And when did you check the spark time wise after the shut down?

Try the crack it will answer a lot of questions.

Dave Neptune :cool:

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I just got back from the boat and boat crack didn't do anything ...

I did remove plug # 1 and plug # 2 ( from front to back ) and they were dry as a Bone .

I did not check the bowl for gas but the sediment bowl was full of gas , I checked for spark the next day , not the night of the stoppage .

what should I do next take of the carb and clean ?

I the crack did not get it to fire I doubt you have spark at the plugs, especially if the plugs were dry. Did you smell gas on the plugs or emanating from the cylinders?

Next confirm spark at the end of a plug wire while cranking.

Be sure the water intake is closed too.

Did you look under the distributor cap? On rare occasions I have seen spark at the coil but not at the end of the plug wire on tose occasions it was a broken rotor.. I had one fail on the frwy in my Corvette once too~~really exciting at that moment:o.

Dave Neptune :cool:

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I too the cap off and looked inside , its not cracked ..

I did bot smell any fuel on the plugs and nothing from the cylinders ..
the water intake is closed ...

tomorrow I will go back and remove plug one and hold against the block to check for spark ?

If have spark , what's next if I don't what's next ?

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BTW the distributor looks as old as the boat ..for what its worth ..

Have you checked your points gap?
Do you have a spare condenser?

Let's check spark at a spark plug while cranking, check for fuel in the carburetor bowl. If both of those checks pass muster (doubtful) I think a compression test is in order. No compression means no vacuum means no fuel/air mix drawn into the cylinders (see motor crack comment above).

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I am on my way to check for spark at the plug and for gas in the mixing bowl .

if I have neither of these or one of these , what next steps

It is pretty rare to lose both spark and fuel at the same time so rather than both let's see if either are deficient, we can chase the possible causes then.

No fuel in bowl
This is s fault in the fuel supply and delivery system external to the engine or possibly a stuck float valve. The recommended next test is to try running off an auxiliary tank.

Spark at the center coil wire but not at the plug
Possibilities are the rotor, distributor cap, plug wire or spark plug itself.

As long as you're there
It's easy to do a crude compression test by putting your thumb on a spark plug hole (plug removed of course) and cranking the engine. You should not be able to hold your thumb on the hole as the air pressure pushes against it.

All of the above three test good
My thoughts immediately go to timing.

I went to the boat to check : the carb bowl had gas and it leaked out when I opened the set screw ... the sediment bowl which , I had emptied yesterday is now full ( I assume from the cranking I don't know if the is good or bad )
The area under the flame arrestor was dry good or bad I don't know



I performed the thumb test and it was impossible to keep my thumb covering the hole on 1 and 2 ( I didn't do 3 and 4 )

I was all set to report NO spark from plug one and two or the primary from the coil .. when I realized I did not have the key ON ...( unfortunately I only realized this when I had already left the boat )


I was jumping from the starter motor.... and hadn't tuned the key .. Yesterday with the key on I was getting spark from the coil ..


so todays mission only confirmed gas in the bowl , gas in the sediment bowl
and I have compression .. but yesterday I did confirm I had spark from the coil .


I did however notice my water pump cover was leaking from the bottom screw oberdorfer type ...

so tomorrow I go back turn the KEY and check for spark a the plug ..

Tomorrow I'm calling Ken and ordering ..

impeller and new gasket or o ring

points . plugs condenser and coil ...

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Just to report , I was able to get the engine started A new set of points ...