455 engine stalling

I have a 455 olds with an American turbine jet. I have redone the valves, cleaned the heads, replaced all gaskets, replaced fuel lines, fuel pump, and checked the engine for cracks and there are none. With that said, when I take the boat out, after about a half an hour the boat begins to bog down and stall. I have to sit for about 5 minutes before I can start it again and go.
If I keep it at a very low speed, it will go then stall again in a not 10 minutes of use. If I accelerate to half it will bog down and stall immediately. I have put 2k in the engine already! I don't think it's running hot, the water temp is running 120 to 140, if the temp gauge works? Any ideas on what it may be? Thanks for your help! I really want to get on the water again

Re: 455 engine stalling

Hows the spark looking when the engine has stalled? May be worth taking a spark tester with you if you haven't verified this. What about the condition of your carb and filters? How much have you done with those? Are you able to see a squirt of fuel pumping into the venturis of the carb when you make the accelerator pump work (either before or after the stall)? How do your spark plugs read?

Re: 455 engine stalling

^^+1, sounds like you have a coil going south.

Re: 455 engine stalling

Scott Danforth said:

^^+1, sounds like you have a coil going south.

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I may just take it back to the shop. I have 2 separate tanks so I am going to try running the other tank. It had some bad gas in the tank I don't use, so I will drain the old gas and see if the other side runs the same.
The last time I took it out it just seemed that it didn't want to open up either. It didn't go past 2600 rpms at wot

Re: 455 engine stalling

Choppie said:

I may just take it back to the shop. I have 2 separate tanks so I am going to try running the other tank. It had some bad gas in the tank I don't use, so I will drain the old gas and see if the other side runs the same.
The last time I took it out it just seemed that it didn't want to open up either. It didn't go past 2600 rpms at wot

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Ayuh,.... Run it on a remote, removable tank, with fresh gas....

I think yer fuel system is boogered up, 'n it's tryin' to run, Lean...

Re: 455 engine stalling

Choppie, A simple flow test of the fuel pump, and fuel filter maybe in order. It wont cost you a dime to try it either! Hope this helps?