New 5.7 intermittent miss

[XiViperI]

I have a 97 Sea Ray 230 overnighter. I have installed a new long block from michigan motorz. We reused the distributor, the alternator, the power steering pump and the risers. I installed a new quick fuel 650. It has new cap, rotor, wires, plugs and ignition pickup sensor. I also had the original carb a weber 650 installed at first but had the same issue. Basically boat runs beautiful for anywhere from 1 hour to 1 day but no mater what I've tried a random miss comes back. It will spit and sputter like its starving for fuel(timing?). Along with the new carb I installed a fuel pressure gauge and show 4-5psi at idle and 2-3 psi on plane. When the miss starts I still have pressure. I don't know what else to check. Motor runs strong when its running correctly. Fuel vent is ok, anti siphon valve removed for testing. Could it be an electrical issue? Thunderbolt v module? I have a new delco voyager distributor but preferred the thunderbolt for the knock sensor. Any ideas or help would be greatly appreciated.

Thanks!

 

[Scott Danforth]

check the ignition trigger on the T-bolt dizzy. My guess is the new one may have an issue. it is most likely ignition related since it takes an hour for the symptoms to start.

 

[alldodge]

I have a 97 Sea Ray 230 overnighter. I have installed a new long block from michigan motorz. We reused the distributor, the alternator, the power steering pump and the risers. I installed a new quick fuel 650. It has new cap, rotor, wires, plugs and ignition pickup sensor. I also had the original carb a weber 650 installed at first but had the same issue. Basically boat runs beautiful for anywhere from 1 hour to 1 day but no mater what I've tried a random miss comes back. It will spit and sputter like its starving for fuel(timing?). Along with the new carb I installed a fuel pressure gauge and show 4-5psi at idle and 2-3 psi on plane. When the miss starts I still have pressure. I don't know what else to check. Motor runs strong when its running correctly. Fuel vent is ok, anti siphon valve removed for testing. Could it be an electrical issue? Thunderbolt v module? I have a new delco voyager distributor but preferred the thunderbolt for the knock sensor. Any ideas or help would be greatly appreciated.

Thanks!

I think maybe a weak fuel pump or a restriction in the line. You have pressure on plane but your at bare minimum, and most gauges are not that accurate. How new is the filter?

 

[XiViperI]

Fuel filter is new I even changed it again to be sure. The ignition sensor under the rotor in the distributor is new and the coil is new. I was thinking I should be at 6 psi and I was a bit low. My pump is a new carter (electric) from michigan motorz the one I would replace it with would be a blue holley. But there is a period of time when it runs flawless even at w.o.t. so I'm leaning toward ignition. Should I just install the new delco voyager ignition I have or try to repair the thunderbolt? Since the motor was installed I have replaced the carb and the ignition sensor with no changes. I don't want to keep throwing parts at it even though there isn't many left to replace.

 

[XiViperI]

I think maybe a weak fuel pump or a restriction in the line. You have pressure on plane but your at bare minimum, and most gauges are not that accurate. How new is the filter?

When I had the fuel line off to change the carb I was able to blow into the tank through the pump and filter seemed like it was free flowing. Filter is new.

 

[alldodge]

Fuel filter is new I even changed it again to be sure. The ignition

sensor under the rotor in the distributor is new and the coil is new. I was thinking I should be at 6 psi and I was a bit low. My pump is a new carter (electric) from michigan motorz the one I would replace it with would be a blue holley. But there is a period of time when it runs flawless even at w.o.t. so I'm leaning toward ignition. Should I just install the new delco voyager ignition I have or try to repair the thunderbolt? Since the motor was installed I have replaced the carb and the ignition sensor with no changes. I don't want to keep throwing parts at it even though there isn't many left to replace.

Take your timing light and put the pick up on the coil wire. Take someone with you to see if the strobe is steady or you see a mis.

Edit: 6 is good, I was looking at the possible 2-3 psi. Maybe some clear tubing going to the carb to see if your sucking air

 

[XiViperI]

Take your timing light and put the pick up on the coil wire. Take someone with you to see if the strobe is steady or you see a mis.

Edit: 6 is good, I was looking at the possible 2-3 psi. Maybe some clear tubing going to the carb to see if your sucking air

My current pump only gets 4-5 psi at idle then down to 2-3 on plane. I will try to get it back in the water tonight and see what the timing light does. I haven't tried any clear fuel line but that is a thought.

This is a very aggravating problem to have. Every time I think I have it sorted, bamn! starts to sputter... ugh.

 

[XiViperI]

I decided to install the delco voyager distributor yesterday. I was able to get water run in today and the seems like the miss is gone... So far.. But my timing is a bit off still and I am unable to hit the same wot rpm. I got a El cheapo timing light at Harbor freight and had a hard time seeing it to get the motor timed. So I got it to what I thought was 7° base. But the initial run was OK. But I decided to give it a touch more advance on the water. After doing that it ran more like itself and felt better. I'm going to borrow a better timing light tomorrow and get it closer. Does anyone know what the timing curve should be? Is it the same as the stock 97 non vortec 5.7 motor? I changed the engine to a vortec. Once I set base (again) I want to verify things.

 

[XiViperI]

The delco voyager ignition seems to have fixed my issue. Boat ran great all weekend. I was able to check the timing and adjust the idle mixture, she is running better than ever. Is there any disadvantage to running the delco set up instead of the thunderbolt v? I could buy the the module for that and re-install it if its worth it.

Thanks

 

[NHGuy]

If you did that what would you do with the Delco, return it? If the Delco works set it so you get 32 degrees advance "all in". You can do that by adding the published advance to your base value or by removing the throttle cable and briefly revving it to whatever RPM gets full advance to check. Example if the Delco controller allows 20 degrees advance you'd set the base timing to 12. 20 plus 12 = 32. Vortec heads don't like more than 32 degrees, some guides want 30.