350 Mag fueling problems

qws

Seaman Apprentice
Joined
May 27, 2012
Messages
32
1993 Crownline, 350 Mag Alpha One

Symptom:
Starts up cold fine idles around 600 RPM. About 2 min's after start up the idle gets rough,drops off and dies. Start it back up and give it throttle....to about 2000 RPM....after a min it then dies, and shuts down. By this time it won't restart until it sets for 10-15 mins. Almost acts as if it floods out.

Replaced and tested so far:
Full tank of gas with stabilizer
New fuel/water seperator filter
Confirmed fuel flow from fuel pump
New Edelbrock 1409 Carb, I put this on and its doing the same thing as the orginal Weber. Electric Choke. it is working confirmed. Set my idle mixture screws all the way in and backed out 1 and half turns each. Played with these a little bit and have adjusted them both to a full 3 turns out. Now I'm back to the orginal 1 and half turns.
I noticed my voltage running low 11 when at 2000 rpm. So I did also put a new ALT on it.

Not sure where to go at this point and ideas?
 

qws

Seaman Apprentice
Joined
May 27, 2012
Messages
32
Re: 350 Mag fueling problems

Been doing some searching on the forum. Would it be safe to say I should now start with testing the fuel system- boat side?
 

spdracr39

Lieutenant Junior Grade
Joined
Aug 30, 2010
Messages
1,238
Re: 350 Mag fueling problems

Are you sure it's not an ignition problem? Could be the ignition coil getting hot and losing power. Check for spark when it won't start.

Saw another thought from a different post. Loose or bad ground could cause the voltage to drop and the ignition to lose power.
 

qws

Seaman Apprentice
Joined
May 27, 2012
Messages
32
Re: 350 Mag fueling problems

I was able to do a little more troubleshooting today.
Hooked up a auxillary tank and it acted the same, no change. After it had run a bit and stalled we removed the flame arrester and pumped the throttle but no gas came thru the jets.
Even though I did confirm that the fuel pump is pumping gas is it possible my fuel pump is bad?
We haven't gotten to the ignition just yet but we did check to see if the ignition coil was hot and it isn't.
 

qws

Seaman Apprentice
Joined
May 27, 2012
Messages
32
Re: 350 Mag fueling problems

No opinions on the fuel pump?
Been searching the forum trying to find out what to look for when you pump the throttle and get no gas thru the jets but can't seem to find anything yet.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,241
Re: 350 Mag fueling problems

No opinions on the fuel pump?
Been searching the forum trying to find out what to look for when you pump the throttle and get no gas thru the jets but can't seem to find anything yet.

Ayuh,.... Welcome Aboard,.... If there's No gas gettin' to the carb,...

Either the fuel pump ain't pumpin', or the tank ain't givin' up it's fuel...

The pump should be providin' 5 psi of fuel pressure to the carb...
 

qws

Seaman Apprentice
Joined
May 27, 2012
Messages
32
Re: 350 Mag fueling problems

Found so far

Fuel pump is pumping at 30psi. this was replaced just 2 years ago
Also found a bunch of debrie coming up from the tank.
 

Failproof

Petty Officer 1st Class
Joined
Sep 26, 2011
Messages
273
Re: 350 Mag fueling problems

30 psi? Ummmmm, yeah at that pressure your carb is a flying toilet bowl!
 

qws

Seaman Apprentice
Joined
May 27, 2012
Messages
32
Re: 350 Mag fueling problems

The marina mechanic installed the new fuel pump. He also drew some fuel to show me how much water was in there. In a qt container it was almost 3/4 water, 1/4 fuel. Confirmed pressure and cleaned out the new carb. He ran it twice. Once when I was not there an the other time when I was. Sounded great, they even took some Sore fuel to show me out much better it looked. He did tell me I may not be out of the woods yet though. Aside from him putting in a new fuel/water filter he also gave me another to have in the boat per my request. He then told me to run it for 20 min's and check the filter fuel to see if it looked good.
So we go to the lake, dump it in and it started right up and never sounded so smooth. Idle was perfect. So we proceed to run it. Ran it for the 20 min's or so. I was a very happy camper!...... THEN..... while doing about 40 mph I hear a snap and the motor quits! Went to restart and the 2 batteries all of a sudden were just barely cranking over. Finally it started but stalled immediatly. This happened a few times. Anyways we had it towed back in. I dumped the filter fuel into a clear container and it looked ok. I removed the carb and have it home with me know apart and getting ready to clean it. It really doesn't look all that bad. Just some small particles. I'm thinking of changing out the fuel line to the tank with a new hose. Any other ideas you may have to add to what I'm doing?

I'm about ready to call it a season. This has not been my year.
New Top - $750, Wet sand and detail $600, Replaced the bellows $1200, picked up the boat and found a huge dig about 4 inches long thru the gel coat. That marina claims they will pay for it. Carb $400, Alt $125.. misc materials $100, Last visit to a new marina for the above problem $500= $3500 +, and I've only been on the water for 20 mins!...
 

qws

Seaman Apprentice
Joined
May 27, 2012
Messages
32
Re: 350 Mag fueling problems

For those of you that come across this in a search. My advice is use the Adult Stickey section of this forum. That is your best place to find answers. Don't bother wasting your time posting symptoms,what you have done and then ask for additional help, from the looks of it theres not much here.
btw... I've spent an additional $400 today on batteries and all new ignition parts. I'm no further ahead.... and YES... this boating season can kiss my butt!
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: 350 Mag fueling problems

Ok lets start over..New ground but simple

1 check every electrical connection on the boat and clean it..boring yes but very simple boats are different but very simple. Horn bilge pump dash board main bus system battery connection's running lights simple stuff but tedious until you know it. Every connection on the boat

OK carb this is 40 yr old stuff disconnect the fuel line from the carb...take a rubber tube and attach it to the carb line make sure the line is out of the boat..take very careful aim your about to squirt fuel at 30 psi it should be a gusher..like a garden hose..if so change your pump to a 6 psi pump take that pump back to your MARINE mech and ask him where he left his mind. Mech fuel pumps just squirt and squirt and squirt and cant achieve 15 psi...Laughs a bit if you do that be damm careful 20 psi can push one hell of a lot of fue i doubt very much you have that much going on...is it a elecrical pump?


Ahh find where your tank inlet hose goes to...there should be a a cap you can unsrcew and open up the tank drain the fuel and look for debris..actually if you do that take a garden hose and flush it out thourghly...fill it to the top with gas when done and then use something call HEAT it will take out all the mositure and it work's just use one can every fill and by summer's end it will be good..To that point you have already taken over a half gallon of water out a cupful may remian after doing something like that...BY THE WAY BATTERY OUT OF THE BOAT>>NO POWER TOOLS PRESENT..

Do all that and see what happens..dont spend anymore dough its time for sweat equity...and careful steps.
l
 

qws

Seaman Apprentice
Joined
May 27, 2012
Messages
32
Re: 350 Mag fueling problems

Ok lets start over..New ground but simple

1 check every electrical connection on the boat and clean it..boring yes but very simple boats are different but very simple. Horn bilge pump dash board main bus system battery connection's running lights simple stuff but tedious until you know it. Every connection on the boat

OK carb this is 40 yr old stuff disconnect the fuel line from the carb...take a rubber tube and attach it to the carb line make sure the line is out of the boat..take very careful aim your about to squirt fuel at 30 psi it should be a gusher..like a garden hose..if so change your pump to a 6 psi pump take that pump back to your MARINE mech and ask him where he left his mind. Mech fuel pumps just squirt and squirt and squirt and cant achieve 15 psi...Laughs a bit if you do that be damm careful 20 psi can push one hell of a lot of fue i doubt very much you have that much going on...is it a elecrical pump?


Ahh find where your tank inlet hose goes to...there should be a a cap you can unsrcew and open up the tank drain the fuel and look for debris..actually if you do that take a garden hose and flush it out thourghly...fill it to the top with gas when done and then use something call HEAT it will take out all the mositure and it work's just use one can every fill and by summer's end it will be good..To that point you have already taken over a half gallon of water out a cupful may remian after doing something like that...BY THE WAY BATTERY OUT OF THE BOAT>>NO POWER TOOLS PRESENT..

Do all that and see what happens..dont spend anymore dough its time for sweat equity...and careful steps.
l

A real response... Thank you.
Now, I did replace the fuel pump to a 6 psi. (its mechanical). Please see above where I wrote that the mechanic is the one that found the 30 psi pump and he then replaced it with a new one and checked pressure.

Today I went thru all the electrical connections and cleaned anything that showed corrosion. In the process of this I did a tune up sorta speak. I replaced the ignition coil, pickup, cap. The batteries were 4 years old so I also replaced those with new connections as well. I'm doing all this at my slip and gets very frusterating in the hot sun and trying to squeeze myself in there to work on this. I did loose 2 of the screws for the distributer cap... and of course the new cap doesn't come with any. I used zip ties for now until I can figure out who sells the screws.

After this I was able to get it running again. But stayed at the dock only at this point. I could rev up and it held idle at 700 rpm. I'm a bit afraid to take it out since the last time it just quit after 20 min's.

Is it recommended that I change out the gas completely or should I just throw a bottle of HEAT in the tank and continue on? BTW, where can I purchase it?
Why is it when i had a fuel pump in there and it was pushing 30 psi the carb never flooded out? I'd like to know in hopes of maybe that will help me.
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: 350 Mag fueling problems

You have old boat and so do i. Todays fuel is laden with alcohol and thats very hard on hoses very. It can eat them like they were sugar candy..ive seen it wish i had taken pics it also chemically razors cleans the entire fuel system. So all that crud ges up hill and at some point its filtered and trapped or it plugs or gumbs up the whole system.

Cleaning the tank is a simple thing for me during the seventies i cleaned more than anyone should so its just std operating procedure for me..thats up to your discretion. As to heat it just evaporates water..keeps cars from frezzeing there lines in extreme cold weather..it will not clean a thing.

http://www.goldeagle.com/brands/heet/faq.aspx

Just a note you may have contaminted your new carb with junk from your fuel system one never know's until it fails.....That is why i just cleaned the whole system on both of my tubs..Good Luck
 
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