Canbt get low idle 351 Ford PCM

"94 Sport Nautique Pro Tec ign

"94 Sport Nautique Pro Tec ignition. Had carb rebuilt after same problem last year; ran/idled great although electric choke wasn't working well (had to manually close the choke to get a cold start). Ran the same this year until last weekend: 2 days great, then next day couldn't get to run at idle speed. Had to adjust idle speed way up to stay on the lake. Blew dark smoke and fuel out the back. Any thoughts/tips would be appreciated

Unrelated (?) problem: tach was not working correctly. It would sit at zero until the engine revved then peg at 4100 rpm and sit there even after throttling back. Tapping the guage returned it to zero. Any chance these issues are all interrelated?

Last question: where does the Tach pick-up its signal? Thanks in advance"

let me guess you have the POS

let me guess you have the POS Holley Carb... get rid of it. you will lose a little performance with the edelbrock look alike but the hassle factor is worth it. one other thing you can check is that the bolt/clamp that holds the electronic ignition module (where the distributor would go) isn't loose and the module rotating and screwing up your timing. you could have a stuck float in your carb too. you might simply try tapping on the top of the bowls while at idle and see if it helps. it will re-stick again though and may require new needle and seat. tach thing happened to me as well. it just doesn't register well when the boat is gurgling at idle. i have two of these POS PCM's with holley. both did same thing. they are 1992's. i replace the carbs and all is well