Part # Question and intermittant miss

[CajunCopper]

Looking at replacing my power pack because of a intermittent miss.
Model#: 1989 J200STLCEB
Ser.#: Q 02270828

I have been battling rough idle, intermittent high speed miss, occasional short loss of ignition while running. I've replaced VRO, timer base, plugs, wires, primer bulb, fuel filters, checked for air leaks, looked for loose wires and grounds. I have looked under the power pack and it appears to have gotten hot at one time and melted some wires. Someone before me taped and replaced some of the wires. When it idle smooth, it is nice and when it runs fast it is nice. Idles good 30% of the time and runs good through the rpms about 80% of the time. Compression is 74 low to 80 high. A shop did this for me so I'm not sure if it was hot or cold. I run a can of Seafoam in almost every tank.

I thought I would explore the idea of replacing the power pack. My power pack has the number 583905 on it. Can't find this part number anywhere. What is my correct part number?

Thanks,

[ChampioNman]

586667 is the number you need. Have you tested your recirc valves? They sure can raise cain with idling.

[CajunCopper]

No I haven't. I need to do some research on that as to how to check it.

This thing will idle at 800rpms and sound like a champ, smooth, quiet, shifts great, I'm proud to own it. Then it runs up to about 1000 or 1100 and sounds loud, rough and makes shifting not as easy. It varies from nice to not nice often.

I'll start researching your idea.

Thanks

[ChampioNman]

If you are at idle on the H20 and you raise and lower the trim does the rpm change? To test your recirc valves follow the hoses from the block to the intake manifold right behind the carbs at the end of each hose is a recirc valve. Use a 5/16" socket to remove them. Take one of the hoses and try to blow air through it if you cant then the valve is good as it is a one way valve. On the motor side of the valve it has a screen on it that may be clogged. You can soak it in isophropyl alcohol and see if that cleans them up.