Mercruiser inboard issue

[epupa]

I have just acquired a 2000 Albemarle 28 with twin Mercruiser 350 MAG inboards. There are 2 automotive fuel pumps at the Racors in the engine room. They are wired directly to the ignition switch, not through the oil pressure switch. My understanding is there is a low pressure and a high pressure fuel pump on each engine. Is that correct? <br /> <br />After speaking with several people I understand there may have been a service bulletin concerning a vapor lock problem due to poor air circulation/intake in the engine room of some vessels. Can anyone assist with information or does anyone know of the difference between the marine and automotive pumps. The vessel is currently at the Albemarle dealer in Morehead City, NC, and he is also trying to get data from Mercruiser. <br /><br />The Mercruiser model number is 344559JM1, serial numbers OL391497 and OL391494, manufactured in 1999.

 

[BRIAN03]

Re: Mercruiser inboard issue

If you keep the fuel under pressure it will not vapor lock. On the Mercruiser the electric fuel pump is located half way in the fuel system. The vapor lock problem occurs right befor the electric fuel pump. If you keep the fuel under pressure the problem will not occur. Mercruiser came out with alow pressure fuel pump as an add on kit to the fuel system. The low pressure fuel pump come in a box with no part number. The extra fuel pump is wired in to the main fuel pump wiring. I used the holley electric marine fuel pump when this problem first started to show up. If you keep the fuel under pressure by 2 psi it would not vapor lock. ABYC states the fuel pump must be with in a foot of the engine and wire thru an oil pressure switch. After making many calls to Mercruiser they sent us low pressure fuel pump kits with no part numbers and stated there was no problem. Volvo puts there electric fuel pump on the beginning of there fuel system. Every engine we added an extra elecric fuel pump to the vapor lock problem went away.

 

[rodbolt]

Re: Mercruiser inboard issue

hello<br /> yep what Brian03 says plus a warning. you must remove any non-coast guard approved fire starters. and the ones remaining MUST be installed and wired in accordance with current standards and practices. we have a lot of funky crap coming up from down south someplace. when they get to here I have to ground the boat until it is either fixed properly or the owner signs a release stating he has been notified of a safety defect or non-compliance and leaves the marina complex with the boat still not repaired. I will let it be someone elses problem. gasoline safety and electrical safty I dont take lightly. I have a 28 albermarle that just arrived from that area thursday night. I inspected it yesterday. it has MAJOR safty issues and will not be worked on or allowed to stay if they are not corrected. its a matter of I dont mind if you catch fire just dont catch the rest of us on fire as well.<br /> sorry about the rant but its terrible when someone gets here and I have to hit them with 5 or 6 hundred in repairs to correct a defect they just paid to have installed. I had another a few months back that the filter was leaking and dripping fuel everywhere bucause the pump just kept pumping. I dont like putting any pump on the inlet side of a filter and there are some specs as to the type of fittings and tubing to be used under pressure and hose and clamps usually are not included in an enclosed compartment. most of the vaporlock problems I deal with are excessive fuel system vacum. if vacum is over 4"hg then you must find and rectify the problem even if it means changing everything to 1/2" fuel lines and solinoid type antisiphon valves. most people have no clue how to select an anti-siphon valve and will just grab one off the shelf and screw it on and never know the problems they create. <br /> good luck and keep us posted as to what happens.