Location of fuel boost pumps on 280DA

Gunn

Well-Known Member
TECHNICAL Contributor
Oct 4, 2006
2,335
Potomac River - MD
Boat Info
2003 280DA and 1995 Sea Ray 175
Engines
Twin 4.3l and 3.0l, all w/ AlphaI GenII drives
So I am finally going to install fuel boost pumps on my twin 4.3MPI engines to hopefully once and for all fix my vapor lock problems I've had over the years.

My simple question is...for those that have them installed on their 280DA (or similar twin engine Sea Ray), where is the boost pump and fuel filter mounted for each engine? Pics would be great!

It doesn't look like to be the easiest of jobs (nothing ever is in the cramped space of this engine room). I have electric fuel valves and fuel filter/water separater in the line going to each engine. I need to add an in-line filter ahead of the boost pump, and then the boost pump into this mess. It looks like the electric fuel valves may need moved to accommodate all this. Just curious how those that have them, had them installed.

Thanks,

Tom
 
It's funny you bring this up. I experienced my first vapor lock issue on Saturday.......
 
I know this is an old thread, but I'm wondering if Tom installed the boost pumps and if it fixed his vapor locking problem.

I currently live (and now boat again finally) in Las Vegas and I've run into what seems like vapor lock. It happened to me in North Carolina too the years I was there ('10-'13).

I hope you got your problem fixed, Tom!

Doug

Sent from my SAMSUNG-SM-G890A using Tapatalk
 
I usually try to be good about posting follow-ups to threads...sorry I left this one open-ended. (I update it now because I saw Doug is still experiencing this issue, a year after making the previous post above).

YES I did fix my vapor lock problem. And it was installing the boost pumps that did the trick, 100%. It has never once happened since I did that, and I regularly boated in the same summer conditions that would cause it to happen.

I used two Airtex E84389 fuel pumps (~$70.00 on Amazon.com), two inline Mercruiser fuel filters and some fuel hose and did the job. I also made a wiring harness that tee'd into the existing fuel cool fuel pump connection so that when the fuel pumps received power, so would mine. I can find the part # for the wiring connector if you decide to go that route.

As far as mounting, I placed the starboard pumps on the starboard wall (gunwale?), behind the vacuflush system. Routing was easy from there, between the electric fuel valves and the spin-on fuel filters. For the port side, I mounted the fuel pump right under the water holding tank (and right under the storage for the cockpit table), right next to the electric fuel valves.

It's been two 3 full boating seasons since I did this and not one vapor lock issue since! I would experience it all of the time before doing this.

Good luck!
 
I feel like an idiot, but I have a new for me 2001 270 DA with 2 4.3. My question is: what it is a vapor lock? I have no clue!!
 
Being that old you should be carb`d.
With some fuel injection symptoms it was hard/no starting after a shutdown.
the pump is the standard electric pump for a carb`d application to help pressurize the high pressure pump.
 
I feel like an idiot, but I have a new for me 2001 270 DA with 2 4.3. My question is: what it is a vapor lock? I have no clue!!

Vapor Lock is when the fuel vaporizes in the fuel line due to heat, causing air to get into the line. This air then won't allow the engine to re-start. You have to wait for the vapor to turn back to liquid before the engine will start, or somehow force the air out, removing it.

This was/is common in carbureted engines but pretty much went away with fuel injection due to pressurizing the fuel in the line, which keeps it from vaporizing (or at least it takes much higher temps to cause it to vaporize). However, the Mercruiser design of placing the high pressure fuel pump right on the engine means that the fuel line from tank to engine is un-pressurized, which can lead to the vapor lock. Very common in the 200x 280DA's.

Fix is to place another (lower pressure) fuel pump as near the tank as you can get it, to keep the line pressurized. And that is what I did.

Hopefully you won't have to worry about it!
 
I have been experiencing this for a while now I just didn’t know what I was dealing with. After doing research I’m confident this is my boats issue. I have a 2000 270 Sundancer with 4.3’s. To make things worse I had the boat off of the water a month ago and without thinking about vapor lock I filled it up with 87 octane with 10% ethanol (basic car gas) and just now am finding out this aggregates the problem. Any suggestions on additives I can put in the tank to help me minimize the issue until I can run out this gas and fill up with non-ethanol?
 
Switch gas stations, and use a top tier gas, Shell or whatever. It helps, problem being that you have summertime heat but the stations are still pumping winter blend.
 
I live in Florida and the boat is never off the water (except last month) so I am limited to marina gas.
 
So I found in my experience that it made no difference whether I used marina fuel with no ethanol regular gas or from the local station. My boat is at my house so I frequently fuel with normal ethanol based fuel. But I have a marina close if I want to pay extra.

I thought the ethanol fuel was my problem so went through several tank fulls of ethanol free fuel. Made no difference in my vapor lock issues at all. So...don't sweat it. Just use it. The only real fix is a low pressure fuel boost pump...

Tom
 

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