A-4 Engine shutting down after running 45 minutes

[Solitaire]

Fishing for a likely/possible target to my problem. Issue started middle of last season and oddly enough hasn't corrected itself at the start of this season. Almost like clock work after running well for 40-45 minutes the engine starts to hesitate, loose power and shuts down. If I wait for an hour plus I'm able to start up and run for another 40-45 minutes before it shuts down again. I've got good gas, new fuel filter, plugs, clean carburetor and fresh oil. Could my condenser or coil be the likely culprits? Any thoughts much appreciated / 1966 Pearson Triton with a Moyer rebuilt A-4 in 2005. Thanks, Solitaire

[Peter]

points or electronic ignition?

Peter

[JOHN COOKSON]

Here's Some Ideas

Blocked fuel tank vent (this sounds high probability to me): Try venting the tank by running with the fill cap ajar.
Other fuel system problems: Run off an auxiliary tank.
Ignition system problem: Check for spark immediately after the shutdown.
If you have an electronic fuel pump, an OPSS problem: Bypass or short across the OPSS.

Others will be along soon with more ideas.

A BIG WELCOME TO THE FORUM.

ex TRUE GRIT

Edit: Do you have a fuel pressure gauge?

[Solitaire]

Good lead regarding the fuel tank vent, will check that out tomorrow. We do have an electric fuel pump and helpful suggestion regarding checking the spark after the engine shuts down.

I don't have a fuel pressure gauge and after just scanning the forum for similar posts I see many recommendations regarding the benefits of installing one.

[Sam]

Similar problem on my 1966 Morgan about a decade ago. I have points Stumped me for a while until an old harbor buddy said to change out the condenser. Since then I change it out every few seasons with out problems Just be sure to install it correctly on the points post going through the distributor wall. Also, this sounds like classic coil aging breakdown. Low cost replacement fix or consider it. preventative maintenance. good luck.

[roadnsky]

points or electronic ignition?

Repeating Peter's question as it's an important one.
IF it's EI...
Please measure the voltage between the small + post on the coil to the engine block with the ignition turned on and report back.

[Mo]

Knew a guy who had similar issue 6 or 7 years ago. I think we put coil and resistor on it. He also felt like there was a "knock" as the engine started to miss just before shutting down. So the engine would miss and the miss would transmit to the prop shaft and he was noticing it. If that sounds familiar to you something to look at. His run time was 40 minutes to an hour I believe, and then she'd shut down, depending on how hard he was running.

[Solitaire]

Points or Electric Ignition?

Repeating Peter's question as it's an important one.
IF it's EI...
Please measure the voltage between the small + post on the coil to the engine block with the ignition turned on and report back.

Regarding Peter's question, it is electric ignition. I'll see if I can get voltage reading. Thanks