Engine cutting off after a while

[Ctmangrum]

So I have twin1976 Ford 351 Windsor engines and they both will just shut down after running for a while then start back up then shut down again usually at the worst possible time
Coming back to the slip. im switching over to electronic ignition in a week or two as im tired of dealing with points and thought that may be the issue. Doesn't over heat and batteries read ok. What's your thoughts? Thanks.

[km1125]

Do they both shut down at the same time all the time? Are they drawing from the same fuel tank?

I'd honestly try to fix that BEFORE migrating to an electronic ignition. The points-based systems are very simple and reliable, although they do require the periodic maintenance. Definitely a step-up to make that move, it just can cause a lot of headaches when making that kind of migration in the middle of trying to solve an intermittent problem.

[Viper]

There's are several things that will cause those symptoms but we really need more info to narrow down the possibilities. KM brought up a couple of good questions. Would also be good to know;
- do the engines cough and choke before shutting down or do they quit suddenly without warning? This could narrow things down to either a fuel delivery or electrical/ignition issue
- after they quit, will they fire up again right away or does it take a while before you're able to restart them again? How long do you have to wait?
- is this a new condition or has it always been this way since you bought the boat?
- when was the last time maintenance such as fuel filters, ignition tune-ups, etc. were done and have the ignition components been checked?
- Have you checked the fuel filters for water?
- how old is the fuel?
- Are all connections at the batteries and blocks clean and tight? What about the engine harness plugs?

Some possibilities common to that symptom:
- bad or overheating ignition coils
- bad or overheating engine breakers if applicable
- bad anti-siphon valves
- tank pick-up tube screens getting clogged
- tank vents blocked
- fuel system vapor lock
- bad fuel lines
- poor connections

There's more but let's start there.

[Ctmangrum]

So they both don't shut off at the same time. One will start up almost right away and one takes a minute. Don't think its a fuel problem.

[bud37]

QR_BBPOST So they both don't shut off at the same time. One will start up almost right away and one takes a minute. Don't think its a fuel problem.

Have you changed any ignition or fuel system ( pumps) part/components lately or has this been happening since you have owned the boat ?

[Ctmangrum]

Im pretty sure its the distributor components and points i recently changed. Didn't set something right or whatever. Im changing to electronic ignition in a week or 2 so im hoping that will resolve the issue. Just wanted to see if I was on the right track. Seems to be the only thing that makes sense. Recently changed the cap, points, condensor, and coil because I was having some hard starts and now this problem. Ill know if a couple weeks. Thanks.

[bud37]

Just make sure when you buy this new system that you get all the correct compatible components to go with the new system....

.....fyi... points will either work or not...the engine may run poorly but won't run fine and then just quit after a time.....that sounds more like an overheated component somewhere to me.....coils perhaps, as they were changed ( perhaps the wrong spec coils ), bad connections ( loose, corrosion, but both engines ???? ) that get hot, fail then work again after cooling down......you did not say how much time was passing before you could restart.

What is common to both engines ? Your previous post about this was a while back before you changed those components I think from reading back. All I am saying here, is to make sure about the components, don't assume that what was there before you owned the boat was the correct part for the intended service. If the failed part was wrong then replacing it with kind will not fix it.....good luck with the new ignition.

[km1125]

QR_BBPOST Im pretty sure its the distributor components and points i recently changed.

Yea, that would make sense.

QR_BBPOSTRecently changed the cap, points, condensor, and coil because I was having some hard starts and now this problem. Ill know if a couple weeks. Thanks.

Were they the exact same parts - or the correct parts for the application?

Did/do you have an ignition resistor in the circuit?

[Ctmangrum]

So it was the same parts and yes on the resistor but, minimal issues until I messed with them of course.