1977 F30 318 cuts off under load

[Martino]

Checked all the battery cables and found nothing out of the ordinary. However, I have to start the starboard engine first and keep it's rpm's above 1000 in order to start the port engine without the starboard engine stalling.
If the port engine is running first and I try to start the starboard engine it just cranks but won't kick over. If the port engine isn't running the starboard engine does start.
Ok this is really a pain in the Butt

[prowlersfish]

Do you have a engine synchronizer ? If you do disconnect it .

[Martino]

Do you have a engine synchronizer ? If you do disconnect it .

I just have the strobe light.

[captainmaniac]

Ok... how many batteries do you have, and how are they wired, and if there is there a 'crossover' switch what position is it in?

If basic staring is an issue, it sounds electrical to me. Fuel sucking off the same tank with plugged vent or filters could be an issue, but other answers you have given suggest fuel is not the issue... so maybe electrical...

You should have 2 batteries (one per engine), isolated so each engine uses its own starting battery, both batteries should be good, no battery switch in the 'both' position, etc....

What is your config?

[prowlersfish]

Do you have a engine synchronizer ? If you do disconnect it .

I just have the strobe light.

Disconnect it

[Martino]

Well the batteries checked out ok, alternators checked out ok, battery switshes are just the on/off type.

[Martino]

Do you have a engine synchronizer ? If you do disconnect it .

I just have the strobe light.

Disconnect it

How would the strobe light help if I disconnect it?

[prowlersfish]

I just have the strobe light.

Disconnect it

How would the strobe light help if I disconnect it?

The synchronizer / strobe can short one engines ignition system to the other . Seen it more then once

" If the port engine is running first and I try to start the starboard engine it just cranks but won't kick over. If the port engine isn't running the starboard engine does start."

[Martino]

Disconnect it

How would the strobe light help if I disconnect it?

The synchronizer / strobe can short one engines ignition system to the other . Seen it more then once

" If the port engine is running first and I try to start the starboard engine it just cranks but won't kick over. If the port engine isn't running the starboard engine does start."

So if I disconnected the wires to the strobe so it isn't working as opposed to tracing the wires through the system would it work that way?

[prowlersfish]

Should

[Martino]

Should

Thanks for the advise !
I'll let you know what happens

[Martino]

Should

So I disconnected the wires from the strobe and the engines wouldn't fire up. So I wired them back up. Didn't realize the strobe had a round dile type knob. I turned it off and both engines are starting in any sequience.
And the starboard volt gauge is working now.
So could it have been the strobe kight ? I hope so !
Thanks again for the advise

[prowlersfish]

Should

So I disconnected the wires from the strobe and the engines wouldn't fire up. So I wired them back up. Didn't realize the strobe had a round dile type knob. I turned it off and both engines are starting in any sequience.
And the start board volt gauges is working.
So could it have been the stove ? I hope so !
Thanks again for the advise

Stove ? I assume strobe sounds like it could be the issue if all is well with it off . The fact it would not run at all disconnected make me wonder about the way its wired causing loss of power else where ?

[Martino]

Should

So I disconnected the wires from the strobe and the engines wouldn't fire up. So I wired them back up. Didn't realize the strobe had a round dile type knob. I turned it off and both engines are starting in any sequience.
And the start board volt gauges is working.
So could it have been the stove ? I hope so !
Thanks again for the advise

Stove ? I assume strobe sounds like it could be the issue if all is well with it off . The fact it would not run at all disconnected make me wonder about the way its wired causing loss of power else where ?

What sucks is I pulled out the wiring schematic for the boat but its just generic. It doesn't show the wiring schematic for twin engines nor does it show the synchronize strobes wiring.

[prowlersfish]

Good chance your boat did not come with the strobe and it was added later .