Dead in the water

[Oshkosh1]

Had my boat out today...19' Wellcraft/230 I6/Merc Alpha 1...Ran great all day, then "Boom goes the dynamite". I was slowing down to a No Wake zone and went to idle, then the engine died. I could crank it...but no fire. I waited 20 min...nothing. I pulled a couple of plugs to see if they were flooded and they were bone dry. I then pulled the "flash suppressor" off of the carb and looked into the throat. Even when there was no throttle applied I could see gas running into it. Now that I think about it...when I went to start it earlier, it backfired when it started...NEVER done THAT before, but I just thought it was "one of those things". Water temp was 175, oil pressure was 40-50 lbs, voltmeter read 14.

I'm not real familiar with carbs...this one has a Rochester 2bbl.

Got a tow in and am home safe but now the work will begin.

Any help will be appreciated as I'm at a loss.

 

[Oshkosh1]

Re: Dead in the water

Oh...Just replaced the coil/plugs/wires/cap/rotor.

 

[crazy charlie]

Re: Dead in the water

Pull dist cap and look inside for moisture.If there is then dry it and try cranking it.

 

[spdracr39]

Re: Dead in the water

Sounds like needle valve is stuck open. Could be the float is cracked and full of fuel so it sinks instead of floating. A kit will include all these things and a rochester is pretty easy to go through.

 

[Oshkosh1]

Re: Dead in the water

Sooooo...I went outside today around 3:00 and just for *****s and giggles, turned the key. IT STARTED!!!!

It fired without touching the throttle...I only let it run about 3 seconds as I: 1. Didn't expect it to start and 2. Had no muffs on it.

I suppose I can discount all but the fuel side of the equation? I pulled the fuel filter...It's a Carter mechanical...It looked REALLY nasty. All crumpled and dirty.

I still think I should go through the carb, however it's an ancient one which is hard to find a kit for. The number on it is 1351-3655A1 Rochester... Can't find any info on it. Can one of you "old salts" steer me in the right direction? Thanks again for the help.

 

[WILSONS88]

Re: Dead in the water

Rochester 2 Barrel or Mercarb 2 Barrel?
Mercruiser has used several different types of carburetors over the years.
The Rochester 2 Barrel Carb was popular on the early 4 cylinder models and it
was also used on a few V6 and V8/305 GM engines as well.

Rochester then stopped production so Mercury Marine designed its own version of the
Rochester 2 Barrel Carburetor called the Mercarb.

The Mercarb and Rochesters were mixed in production models.
When ordering replacement carbs, kits or parts you need to know exactly
which carb your engine has.

One simple test can distinguish between a Rochester and a Mercarb.
The throttle base plate of a Rochester Carb has two idle mixture screws.
The throttle base plate of a Mercarb has only one idle mixture screw.

If you have determined that your carb is a Mercarb, then there is one more
identification you need to make.
The Mercarb came with two different styles of accelerator pumps.
One pump rod was straight and cut off flat at the very top. This was the older style.
The other pump rod has a 90 deg bend at the top. This is the newer style.

This information comes from sterndrives.com

 

[CV16]

Re: Dead in the water

I'd change the impeller. Just a few seconds of running can ruin it, I've done it just to watch my temp go up just about the time I got out of the harbor!

 

[Oshkosh1]

Re: Dead in the water

It's definitely a Rochester...2 idle screws, and the word "Rochester 2 Jet" stamped into it(my first clue!) Although I had the number wrong it's "3635A1".

 

[WILSONS88]

Re: Dead in the water

Here is your carb kit.
The float is also listed on the same page.
http://www.carburetor-parts.com/Rochester_2GC_Marine_Carburetor_Kit_p/4070.htm
The reason I posted that ealier is because the number you provided before would not pull up. The other number came up just fine.
Not sure what year your boat is but if its over 15 years old you might consider replaceing the fuel pump. The diaphrams can get stiff. Mine was about 23 years old and I just replaced it and it solved a bunch of issues I was having.

 

[Oshkosh1]

Re: Dead in the water

After studying the SELOC manual...I have a new theory.

Exhaust Maniflold.

Now follow me on this one...

So it runs great all day, THEN, when I stop for awhile at a sandbar and swim the boat sits. THIS is when it first "popped" upon start up. It again ran well at 3/4 throttle until I slowed for a no wake zone. That's when I noticed that it seemed to run a little rough...almost like it was "missing", but it never died. Idled through the no wake zone, then again ran great 3/4 open(35mph) for about 15-20 min when I stopped at a restaurant for dinner. Again...sat in the water for about 45 min-1hour. Started again with a "pop" but ran good for around 15 min when I came to the final bridge "no wake" zone, slowed and then it finally died. I floated through and was able to moor to a piling where I cranked and cranked to no avail. Thats when I noticed that even when the throttle was in the fully locked position that there was gas STILL draining into the carb throat.

So...could all of this have come from a broken shutter introducing water into the manifold? What would be the typical symptoms of a leaking manifold?

Now understand that it's a foregone conclusion that I will be rebuilding/replacing the carb...just want to make sure one is not just the symptom of the other.

Sorry for the length, just trying to explore every avenue before dropping the money/spending the time to fix it.

Thanks in advance...Your advice/tips are priceless.

 

[Volphin]

Re: Dead in the water

No, you are dumping fuel into the intake and the motor flooded out from too much fuel (over rich condition). The pop you are hearing is possible liquid gas on top of a piston or in the intake. This is not a safe condition to go boating with as fuel vapors can fill the hull and cause an explosion. Rebuild or replace the carb. Also, never EVER look down into the carb while cranking or with the engine running. You can lose some eyebrows! Fuel pump replacement is great advice too. Some mechanical fuel pumps can leak gas into the crankcase and cause oil dilution and crankcase fires.

HTH

V

 

[WILSONS88]

Re: Dead in the water

The shutters are there to keep water from backing up the Y-pipe in the event that it could be forced back up by a wave or whatever.
A leaking manifold usually causes a hydrolock situation. You wouldn't be able to crank it over after it dies. Check out this thread for testing the manifold.
http://forums.iboats.com/showthread.php?t=288629.

I would do the carb rebuild at least.
Have you checked the timing?

 

[Oshkosh1]

Re: Dead in the water

I'm in touch with Flyingfish Carburetors about either rebuilding or replacing it.

I haven't checked the timing...I don't have a timing light, will probably pick one up soon.

As far as the fuel pump...can I replace it with the automotive equivalent(easy to find/MUCH cheaper) and then just but a remote inline filter between it and the carb?

 

[WILSONS88]

Re: Dead in the water

Do you have hard or rubber fuel lines? What year is your boat?
http://www.overtons.com/modperl/product/details.cgi?r=view&i=21632&aID=601A1&cID=SHOPPING
You could do a fuel/water filter if you do not have one.

 

[oops!]

Re: Dead in the water

lets get this one in the right place......our merc guys are top notch.....

asking to have it moved

 

[oops!]

Re: Dead in the water

oops....sorry......thought this was in the general boating....carry on.....

but have you looked at the fuel pump.....marine motors have a clear gas tube that goes from the pump to the carb....if you see fluid running thru this tube....the pump is shot

this is a marine safety feature.....it dumps raw gas into the carb so nothing hits the bilge

 

[Oshkosh1]

Re: Dead in the water

I'll try to answer in order asked:
1. There is a rubber line from the tank to the pump. There is a metal "tube" running about 8" off of the side of the pump with a 45deg bend, then attatched to that is a black hose which runs around/over the front of the valve cover to the carb.
2. It's a 1985...However the motor is NOT original. It's an older Chevy 250/Mercruiser 160 I6
3. No clear tubing from the pump.

I also thought of retro-fitting a fuel/water setup...just not sure of the "details". My take on it is that I would place this between the tank and the pump. Correct?

 

[WILSONS88]

Re: Dead in the water

Yes. It has a line to the filter from the tank, a line from the filter to the pump and then from the pump to the carb. You would probably have to replumb the whole fuel line set up.

 

[Oshkosh1]

Re: Dead in the water

Ordered a fuel water seperator.

I have a new(rebuilt) Rochester 2GV marine carb on it's way from Autoline.

I have a Carter fuel pump with the integral filter. Do I leave the filter element in, or do I need to buy a new pump without one?

 

[fishrdan]

Re: Dead in the water

Automotive fuel pumps will dump fuel on the ground when they go bad, in boat it will dump fuel in the bilge and..... BOOM! So yeah, you need a marine fuel pump. If you add a water separating fuel filter you "don't have to" use the integral fuel filter in the pump, but it's another lines of defense for not getting crap in the carb, so I'd leave it in.

Adding a water separating fuel filter is easy, the hardest part is finding a good location and mount it. For plumbing it in, pull the rubber supply hose off the fuel pump and connect it to the filter, then add another section of fuel hose (marine rated A1) from the filter to the pump. Double clamp every thing with SS hose clamps.