351PCM won't cold start

SupremeWake · Soul Rider Joined: 14 Feb 2003 Posts: 322

I replaced the HOlley carb on my 1986 PCM 351 about a year ago with an Edelbrock performer series and ever since, the boat runs GREAT once started and warmed up. However, at about the same time as replacing the carb, the engine practically refuses to start when cold. I've replaced plugs, wires, ignition coil, fuel pump. Nothing has helped so far. Any other suggestions, ideas, advice would be greatly appreciated. Also, once I do get it started after LOTS of cranking, the engine takes quite a while to warm up. Longer than I think it should take.

Suprahunter · Soul Rider Joined: 28 Apr 2008 Posts: 486 City: Lowell

Take the flame arrestor off pump the throttle once does the choke fully close when the engine is cold.

SupremeWake · Soul Rider Joined: 14 Feb 2003 Posts: 322

Both flaps should be fully closed right?

JTRebel · Outlaw Joined: 05 Sep 2006 Posts: 119 City: Graham

If I remember correctly, PCM carbs had a special base on them to offset the angle at which the motor set. The carb sets at a level position so that the floats are properly alligned. When you replace the stock carb with an aftermarket one you must get a spacer that is like a wedge. This offsets the angle at which the engine sets at so that the floats are at a level angle.

Just a thought

JUST-IN-TIME · Posted: Jun 27, 2008 9:25 pm Post subject:

did u adjust the choke and idle screws

SupremeWake · Soul Rider Joined: 14 Feb 2003 Posts: 322

JTRebel, the new edelbrock carb did come with a little base/spacer that I did put in. I wouldn't necessarily describe it as a 'wedge' though. Maybe I have the wrong spacer? Would that account for hard cold starting, but running and starting again fine when warm?

JustInTime: Yes, I have adjusted the idle screw, but have never adjusted any choke screw. Didn't know it had one to be honest?

JUST-IN-TIME · Posted: Jun 28, 2008 9:47 am Post subject:

i think those are electric chokes right

make sure u r getting 12v to the chke

SupremeWake · Soul Rider Joined: 14 Feb 2003 Posts: 322

yes, it's elec choke. I havent' checked the voltage, but will today.

JUST-IN-TIME · Posted: Jun 28, 2008 9:49 am Post subject:

i would
it should be fully closed in the mornings

SupremeWake · Soul Rider Joined: 14 Feb 2003 Posts: 322

I think it is fully closed, but I'll check the voltage today.

SupremeWake · Soul Rider Joined: 14 Feb 2003 Posts: 322

Ok Update:

It is getting fuel. I pulled the fuel line at the carb and put into a bucket...after just a couple cranks plenty of fuel came out.

When sitting cold the choke is fully closed. I can close it maybe another 1/8" by hand, but thats it.

When I turn the key to the on position, but not cranking, I get about 8-9volts at the choke and at the coil. However, when I apply a battery charger/starter to the batt. I get 13volts at the choke and the coil. I don't understand this because the battery gives me 12-13 volts at the battery. Could it still be a bad batt? Why would using the charger/starter give me more voltage at the choke and the coil?

When I leave the key in the on position, the choke rather quickly opens up and remains in full open position for several minutes as the choke cools down again. This is w/out the engine ever running. Is this correct behavior for the choke? I am not familiar with elec chokes.

Not sure what to do next. Still can't get the boat to fire up at all.

Suprahunter · Soul Rider Joined: 28 Apr 2008 Posts: 486 City: Lowell

The choke is operating correctly. When you said you could close the choke
another 1/8'' did you mean it was still 1/8 open. that's not correct needs to snap closed fully if not, loosen up the three choke cover screws turn the cover until
the choke fully closes. start engine make sure it opens when warm. If you
still need help call me Mike 219-712-5060

SupremeWake · Soul Rider Joined: 14 Feb 2003 Posts: 322

thanks Mike... I'll adjust that choke tomorrow or maybe Monday. I'm still not understanding why I'm only getting 8-9 volts at the choke and the coil though.

JUST-IN-TIME · Posted: Jun 29, 2008 12:05 am Post subject:

charge the battery

Suprahunter · Soul Rider Joined: 28 Apr 2008 Posts: 486 City: Lowell

I wouldn't worry about the 8-9 volts the voltage to the choke is only to open
it as long as it closes fully and opens fully after engine is started its ok

SupremeWake · Soul Rider Joined: 14 Feb 2003 Posts: 322

Mike, you are in Lowell Indiana? I'm in Monticello

SupremeWake · Soul Rider Joined: 14 Feb 2003 Posts: 322

Update: Fired up this afternoon. It took some playing around with the elec choke. I'm waiting for it to cool down again so I can try another cold start, but it was good to hear it run again! Thanks for all the suggestions. I was surprised at how much of a difference even a slight adjustment in the elec choke made. Hopefully, the cold start issue is at least partially solved.

JUST-IN-TIME · Posted: Jun 30, 2008 12:22 pm Post subject:

good deal!