Engine Help!!!
 

When I bought my boat (1987 American Skier with a PCM 351w), I rebuilt the motor and just threw the carb that came on it back on it because I didn't think I needed a new one. First trip out, I discovered that the carb (edelbrock 1406) needed rebuilt because fuel would pour out of the primary venturies. Everything was going ok until about a month ago where every once and a while when you floored the throttle the engine would die unless you backed off, but you could back off and go right back down and it would run. Then last week the lake was really rough and we were hitting some rollers pretty hard to get to a cove to board in. We tubed and boarded for a bit, and then shut the boat off to chill for a while. When I went to start it back up, it didn't want to start. It took a while, but I got it to run so we started idling across the cove to go pick up the tubes. After we got the tubes, the motor wouldn't wrap out and would start backfiring. I made it back across the lake and pulled into the cove our marina is in and it died. Popped of the flame arrestor and fuel was pouring out of the venturies just like it had before. I let it sit for a while and then a guy that knows quite a bit about engines said he'd take a look at it. He tapped on the sides of the carb to make sure nothing was stuck and she fired right up. He also said that him and a buddy of his had this same style of carb on their trucks at one point and had nothing but trouble with them. He suggested I put an inline filter between the fuel pump and inlet on the carb, and replace the carb. So my questions are: Has anyone had similar trouble, should I wait to replace the carb to see if it happens again, and what carb should I replace it with? The 1406 is a 650cfm, and by my calculations, which I don't know much, a 500cfm would be better.

Any help would be appreciated!

I've had several Edelbrocks on various vehicles throughout the years and at one time or another, they've given me some sort of problems. The fuel dumping being one of the more common problems. That said, I have never had one on a boat. On cars and trucks, they run great out of the box, requiring little to no tuning but it seems after a little while, they start dumping gas (and thinning the oil, washing cyl. walls ect.) and become increasingly harder to tune. All of the carbureted boats that I have had, I had run Holleys on them. Not sure why but just always did. They seem to have better fuel control ablility (less sloshing and overflow) but can be slightly harder to tune. Once tuned though, I have better luck with a Holley any day. I don't claim to know much about the Edelbrocks but do know that I've run at least a dozen different Holleys on different boats with little to no trouble. Just look at the hotboats on the lake next time you're out. Very few are running Edels.
As far as the inline filter - definitely and I would run a fuel / water separator as well. Lake gas is notoriously dirty and just using the boat opens you up to having water in the fuel. Water can do some horrible things to the inside of an aluminum carb and I for one have had a 900$ carb ruined by a little water. For a recommendation on either carb that you want to run, call Holley or Edelbrock. They are usually happy to try to sell you the right carb. It doesn't pay for them to sell something that doesn't work for you.

I'll try the inline filter for awhile. I'm worried that my luck would be if I swapped carbs I would have some kind of tuning nightmare and never get it tuned right. A friend of mine also has all of the stuff for an efi swap. Decisions decisions haha thanks for the advice!

The Edelbrock is actually a Carter. Edelbrock just bought them. I ran one on my 455 Olds jet boat for years. You might try just getting a rebuild kit and clean it up good. It is an easy process. Just put everything back the way you found it. Of course if the EFI swap is an option, I would probably do that.

It says weber on the side of it, and it has under 20hrs on a fresh rebuild

I may do efi over the winter, but I don't want my boat to be under construction all summer

A carb meters fuel by airflow so almost any good carb will work as the airflow of the engine will pull in the required fuel. The Carter is a spread bore like a Rochester which is nice on a car but not as important on a boat. A Holley is easier to tune but does not actually meter the fuel as well as the other two.
Basically if you find a four barrel carb from a stock truck it should be pretty good for your boat.

Tapping on the carb and it then running right means the floats/needles were sticking. You can run a bunch of fuel system cleaner through it to help with that but a rebuild is best.

Art is right on. It doesn't take much for the needles/float to stick. Pulling apart the carb and cleaning it good will help, marine engine sit a lot and moist builds up in the carbs. I wouldn't go below a 600cfm for that engine, your calculation is probably right, but you'll have better luck with the 600cfm.

The big reasons I've had to replace carbs was bushings on throttle shaft wore out (vacuum leak) or the carb's body wrapped from heat, etc. But I've used the same carb for 10+ years with just a fresh gasket and clean out every few years on a boat. OH yeah, have had fuel injection for the last 10 years on my boats and love it!!
Cheers,
Dennis