Engine shuts down/Non Responsive to throttle

[rkllogjeri]

So i need some help. I took the boat out for the first time this season and it started just fine, the engine would rev in neutral when the throttle was engaged, but once in forward gear it wouldn't pass 1500 rpm no matter how much throttle was open. i shut down the engine and replaced the fuel filter, no change was noticed. after restarting, an hour later the tachometer flickered and the engine died. we tried to restart the engine but would only die after starting for a moment. after letting the engine cool for an hour it would start again, but no throttle response above 1500 rpm still, and the engine continued to die about one hour into the journey.

any help or suggestion on what might be the culprit?

here's some things I already checked:
the exhaust valve on the gas tank was clear,
fuel lines were clear and flowing
fuel pump pumping fuel
fuel filter replaced

[joec43]

possibly the spark plug wires are reversed

I have found that when it runs well in neutral and reverse, and not in forward that I have reversed two of the spark plug leads.
Easy fix, and worth a check.

Good luck!

[Bob Grenier]

The time laps would make me suspect the coil. Check when it dies to see how hot it is. Do you have electronic or point ignition?

[roadnsky]

Certainly sounds like the coil.

This from Don in another post...
"The most basic three-step method of checking a coil while installed on your engine (and the most fun) is to (1) remove the negative primary wire leading from the negative terminal of the coil to the distributor and installing a two-foot jumper wire (14 gauge or larger). (2) remove the high voltage lead from the coil that installs into the center of the distributor cap and hold it approximately 1/4" from the head or block. Then (3), with the ignition switch on, touch the end of the two-foot jumper wire from the negative terminal of the coil to ground and release.

This is of course exactly what the points do: make and break the negative (or grounding) circuit between the negative terminal of the coil and ground. Each time you touch and then release the jumper wire to ground, you should see a good secondary discharge between the coil lead (that used to go into the center of the distributor cap) and the head or block. The secondary discharge actually occurs when you remove the jumper wire from ground."

Happy hunting...
-Jerry

[rkllogjeri]

Joec43,

i have not messed with the sparks plugs in two years i have owned Sandpur, however i was thinking of changing them as it is being hauled out from the water. Do you know what the order would be? Idon't have a manual on it.

Bob,

I read somewhere in the fourm yesterday that the coil could be it and i have not had a chance to check it. I will. I know that the Coil is next to the engine block, should i relocate it? Thank you for your help

[roadnsky]

Do you know what the order would be? Idon't have a manual on it.
I know that the Coil is next to the engine block, should i relocate it? Thank you for your help

FIRING ORDER:
The plug wires are installed in a clockwise orientation around the distributor cap in the order of the engine's firing sequence (1, 2, 4 and 3). This means that the plug lead from the distributor cap post directly to the right of number one goes to the second cylinder from the flywheel, the next post to the fourth cylinder (at the transmission end), and the lead from the next post to number three. You should then be back at the post for cylinder number one.

COIL
You can certainly move the coil if you suspect it's always getting too hot.
I'd narrow down if the coil needs replacing first...

[sastanley]

I also think it's the coil

Hi, I have very similar behavior to my new-to-me A-4. The engine would purr along at 1,500 RPM for an hour and die off. Repeated restarts were shorter and shorter until by about restart number 4 or 5 it would not stay running. I hunted for a fuel problem for days, and a guy & his three dogs at a prop shop on the Eastern Shore said "have you checked the coil? got a spare? try it!"

I mounted a new coil on the engine room bulkhead, close enough I could still reach it with the high tension wire. I had to lengthen the other wires to the coil (+) & (-) posts. I have had no unplanned shutdowns since, but only have a couple of hours on the motor since the coil replacement.