PCM 351 mods

[Hematoma]

Just curious what some of you guys have done to your 351's to make them more reliable or run better? I don't mean mods to make more power so to speak just piece of mind mods.

1. I replaced my entire ignition system last season with Fords Duraspark setup. Went down to the parts house and picked up a Complete ignition for a Bronco Coil, distributor (yes its sealed) and ignition box. I went this route so if something eff's up I can go to the local parts house and be back on the water same day no ordering parts. Just in case someone wants to do this setup IT'S NOT PLUG AND PLAY you have to get the wiring diagram off the net. It has been a nice upgrade my boat idles and runs very smooth.

2. I got rid of the eff'n choke and choke plate. My boat very rarely has seen cold temps and even when it has its started up just fine. I contribute that to good tuneing skillz lol. One less thing to go bad and cause irritation

3. Seafoam Seafoam Seafoam I swear buy this snake water. It's night and day when used. Some people don't like it but I think it works.

Anyways whats somethings you guys have done maybe it will help others with a better running boat.

P.S. If anyof you guys are having a hesitation from idleing to full power like when your pulling someone out of the water? Check your accelerater pump adjustment. Take the flame arrestor off and have someone move your throttle or move the linkage yourself slowly. If you don't see immediate fuel squirting into the carb your adjustment is out of time. Their is a cam on the linkage that moves the pump arm, adjust the screw on the pump arm so that as soon as you start to move the linkage fuel starts squirting. This is per the Holley website. Your off idle performance will be night and day if adjusted correctly. Just a heads up.

[michael hunter]

Hema how long do you have to warm it up before you can go?

[Hematoma]

Hema how long do you have to warm it up before you can go?I don't bro, literally I start it, I lift the engine cover for a visual quick look (make sure there is nothing unexpected going on) and back up. Then I let her idle while I wait for the fam to get on the dock. I have never had a problem with it stalling when cold. Back when I got the boat the choke was messed up so I just took it all off and have never had a problem so I never replaced it.

[csuggs]

If I have been sitting for a while idling, or maybe with the motor off, then I fire up and start to pull, sometimes it will stall. This never happens when it's warm. So what's up with that?

[Hematoma]

Also you have to take in that when I got the boat the motor was freshened up quite a bit. Both water pumps, alternator, starter, full ignition upgrade plugs and wires all changed for new. I rebuilt the carb and did a compression test which turned out to be very good to my surprise considering its age. I've always been into performance motors and always believed that a good tuned motor does'nt need to be choked to start, but living in warm climate does help. I would'nt suggest removal on a suspect motor or in cooler climates.

[Hematoma]

If I have been sitting for a while idling, or maybe with the motor off, then I fire up and start to pull, sometimes it will stall. This never happens when it's warm. So what's up with that?Your carb might need a little TLC. Sounds like a dripping jet and the fuel is puddleing up in the intake. when its warm the drip is just vaporizing but when cold its wanting to flood it out a bit.

[mapleleaf]

Just installed my new electric choke (from DIM), cuz my 351 won't idle worth a split when cold....still having too pump throttle and hold it to let'er warm up (I'm up NOrth)
Carb's been rebuilt, but I'm know tuning wizz, also having trouble in drive at it's slowest speed, tries to bog down and die........HAVE to add throttle...
More load on the e. choke spring????
Help, I want my boat to run like your's......

[Hematoma]

Just installed my new electric choke (from DIM), cuz my 351 won't idle worth a split when cold....still having too pump throttle and hold it to let'er warm up (I'm up NOrth)
Carb's been rebuilt, but I'm know tuning wizz, also having trouble in drive at it's slowest speed, tries to bog down and die........HAVE to add throttle...
More load on the e. choke spring????
Help, I want my boat to run like your's......Maple I have my idle up to about 850rpm seems to help the reaction from idle to full power when pulling someone up. Some people will be like thats to high but I dont sit and idle for long periods of time, when we change out riders the engine gets shut off. Personally I would try turning up your idle a bit and see if it helps with the warm up process.

[mapleleaf]

word......the idle was set low, tach messed up so we did it by ear...

[csuggs]

For what it's worth, these boats (at least the 351) was set up from the factory to idle at 600 in gear, which probably translates to about 750 or 800 in neutral.

[Mani]

I don't bro, literally I start it, I lift the engine cover for a visual quick look (make sure there is nothing unexpected going on) and back up. Then I let her idle while I wait for the fam to get on the dock. I have never had a problem with it stalling when cold. Back when I got the boat the choke was messed up so I just took it all off and have never had a problem so I never replaced it.


That's the exact same thing I've been doing since the rebuild. I never wait around for it to warm up anymore. Once I pull of the trailer, I take it for one quick spin until everyone's at the dock. That's about 1 full minute from the time I start her. She's almost up to full temp by then.

I do appreciate your advice on the idle hesitation. We've been having that problem very regularly. Last season it would die. This season, with it all rebuilt, it just bogs down for a split second, but I'd rather have it running like yours. I'll give the adjustment a shot, and get back to you.

My favorite mod, being that it is my only engine modification from stock, is the 105 amp alternator from DB electric. It gives me piece of mind on the water. I have been towed due to dead batteries before, and this thing let's me know we won't have that specific issue again.

[Hematoma]

For what it's worth, these boats (at least the 351) was set up from the factory to idle at 600 in gear, which probably translates to about 750 or 800 in neutral.True, true, I have read quite a few threads here and there about people setting the idle at 600rpm while doing the ignition timing and just leaving it.

[Hematoma]

Another change I did which slipped my mind was I changed from the 140 degree thermostat to a 180 degree. The lakes here in Az are fed by snow runoff so they stay pretty cool for the most part. Example it was in the 102 air temp range and ScottAz got 63 degrees and 70 degrees water temp readings. With the 140 my boat did not want warm up at all, even after cruising around I switched to the 180 and good to go. She now averages 180 degrees all day. Something to think about if your water temps your area are on the coolside.

[mapleleaf]

Another change I did which slipped my mind was I changed from the 140 degree thermostat to a 180 degree. The lakes here in Az are fed by snow runoff so they stay pretty cool for the most part. Example it was in the 102 air temp range and ScottAz got 63 degrees and 70 degrees water temp readings. With the 140 my boat did not want warm up at all, even after cruising around I switched to the 180 and good to go. She now averages 180 degrees all day. Something to think about if your water temps your area are on the coolside.

That's got to be the ticket, In 65 water this past week she would hardly warm up past 150, weird cuz last year she ran a solid 160....maybe I go do dat thermostat...

[Hematoma]

That's got to be the ticket, In 65 water this past week she would hardly warm up past 150, weird cuz last year she ran a solid 160....maybe I go do dat thermostat...Bingo Maple, last season my boat ran in water temps that averaged 80-90 degrees. I moved out here to Az in the beginning of the yr and it wouldn't get above 150 because of the cool ass water.

[mapleleaf]

sh-boy.........