Inboard 350 dies

[Fully_Loaded1]

OK I have a non vortec 350 with a less tha 100 hour mallory distributer and a new coil. I also have a new fuel pump and carb on it. The issue is after I start it up cold, starts up perfect and will idle, and let it run for 20-30 min. at idle it will die. Sometimes it will crank back up fairly quickly and sometimes I have to let it sit a minute or 2. After it dies the initial time it will only run 2-5 min. before dying again. At first I though it was a fuel problem but I am leaning more towards the ignition cutting out because after the last time it died I poured gas straight in the throat of the carb and it did not restart or even hit. Ignition switch is new and voltage at the coil remains even after it dies. I have been trying to get this figured out for over a week now with no avail. I just got the boat put back together and have not been able to put it in since I got the motor in. Any help will be greatly appreciated.

 

[ChrisCraftJohnny]

Re: Inboard 350 dies

Are you using the new Mallory Marine Ignition kit? Or are you using some Mallory parts with the Thunderbolt IV or V system module?

Johnny

 

[Bifflefan]

Re: Inboard 350 dies

Mallory is famous for the electronic eye used to trigger the ignition,
it will give you a headache you will never forget.

If you have one these, there is a retro kit to change it to a magnetic trigger. These are extremely better, I cant stress how much better.

They will do just what you are talking about, without much rhyme or reason.

 

[Fully_Loaded1]

Re: Inboard 350 dies

Are you using the new Mallory Marine Ignition kit? Or are you using some Mallory parts with the Thunderbolt IV or V system module?

Johnny

i did not install the unit but it is a Mallory model YH with an accel coil. It is straight mallory no mercruiser parts. It is a ballast resistor, accel universal coil, and the distributer.

 

[Fully_Loaded1]

Re: Inboard 350 dies

Mallory is famous for the electronic eye used to trigger the ignition,
it will give you a headache you will never forget.

If you have one these, there is a retro kit to change it to a magnetic trigger. These are extremely better, I cant stress how much better.

They will do just what you are talking about, without much rhyme or reason.

How can I tell if it is magnetic or optical? I can only see the sticker where it says model YH

 

[dubs283]

Re: Inboard 350 dies

is the choke opening when the engine warms up??

 

[Fully_Loaded1]

Re: Inboard 350 dies

is the choke opening when the engine warms up??

Yes

 

[CV16]

Re: Inboard 350 dies

My dads boat was doing the same thing. Out of frustration, I put in a different coil. It seems that the problem went away for now. His boat would run good for 20-30 min, then just die. It never did like to idle for very long. After the new coil, I let it idle for over 2 hours and it never missed a beat. I just happened to have a new coil from an old outboard hanging in the garage, so it cost me nothing. Just make sure if you try a different coil thet you know if it has an internal or external resistor.

 

[Fully_Loaded1]

Re: Inboard 350 dies

My dads boat was doing the same thing. Out of frustration, I put in a different coil. It seems that the problem went away for now. His boat would run good for 20-30 min, then just die. It never did like to idle for very long. After the new coil, I let it idle for over 2 hours and it never missed a beat. I just happened to have a new coil from an old outboard hanging in the garage, so it cost me nothing. Just make sure if you try a different coil thet you know if it has an internal or external resistor.

I am kind of glad you mentioned that as I was thinking of replacing it again tomorrow so you kind or reaffirmed my thoughts. Would it recrank right after it died?

 

[Vanover]

Re: Inboard 350 dies

Not really sure about the mallory set up, but ignition modules will do just what you describe after heating up. You can remove it and get it tested. Test it like 5 times in a row. If you are cranking and see no movement of the tach this is a sure sign. If you don't have one of these disregarad.

 

[Fully_Loaded1]

Re: Inboard 350 dies

Not really sure about the mallory set up, but ignition modules will do just what you describe after heating up. You can remove it and get it tested. Test it like 5 times in a row. If you are cranking and see no movement of the tach this is a sure sign. If you don't have one of these disregarad.

View attachment 67355

Do not have HEI but the ignition module did come into mind. Supposidly it is almost new and looks it on the inside. God point about looking at the tach. I will check that out tomorrow to see if it is moving after it dies. I did look and I cannot figure out how to get the module out of the distributor, tomorrow is another day and I have a couple of things to look at.

 

[Vanover]

Re: Inboard 350 dies

good luck. They are normally burried in there pretty good. I know i have had a couple that looked good but failed after getting hot. I solved my issues by getting a good name brand unit from MSD. Good luck keep us posted.

 

[Fully_Loaded1]

Re: Inboard 350 dies

Well I had an old 302 laying around so I tested the coil with a meter and it tested good so I slapped that bad boy on there. Ran it for about an hour onthe hose and all seemed good. As soon as I get my steering ram back from the hydraulic guy this week I will be water testing. Keeping my fingers crossed. I also noticed that my engine temps came up about 15 degrees after installing this coil. Before it was running about 155 - 160 now it is at about 170. My guess is the "new" coil I had was always weak and this coil is throwing the proper fire bringing the temp up to where it is suppose to be.

 

[Vanover]

Re: Inboard 350 dies

glad you got it sorted out for now. Its nice to have everything in working order when it comes to these darn boats.

 

[6meter]

Re: Inboard 350 dies

Good to hear its running. Never liked the Accel coil. Hear problems all the time.