Fuel Pump Rebuild Questions

[Fishallot]

After being so frustrated with my water pump install try (see my other post) I decided to try saving my ego by tackling another project, rebuilding my fuel pump. Everything went well and my primer bulb pumps tighter than it ever has. My motor is a 1993 115hp 4cyl.<br /><br />The question I have is about the new check valves that I installed as they were different from the old ones. My old check valves were rubber and had a small plastic disc over them. The new check valves in my rebuild kit were only a large plastic disc. The below pic shows my old check valves out of the pump and the new ones installed in the pump.<br /><br />

<br /><br />Are these new plastic check valves an upgrade to the old rubber ones or did I get and install the wrong parts? The rebuild kit I purchased was a Quicksilver kit, part number 857005A1.<br /><br />I also noticed in my Clymer manual that 75-115 hp. motors are supposed to have 2 oil holes in the boost diaphram to allow incoming oil to mix with the gas. The boost diaphram that I took out of my fuel pump as well as the new one I just put in didn't have these two holes. Does anyone know if these 2 oil holes are really supposed to be there?<br /><br />Like I said everything seems to be working fine, I just want to make sure that I put in the correct parts.

 

[Elmer Fudge]

Re: Fuel Pump Rebuild Questions

What i've always done, is place the plastic disc over the rubber valve and fasten it down by inserting the retainer as shown in photo.<br />I've never encountered any problems doing it the way which i've discribed.

 

[Fishallot]

Re: Fuel Pump Rebuild Questions

So what your saying is that the new plastic disc was suppossed to only replace the old small plastic disc not the rubber check valve too? I'm supposed to still have the old rubber check valve under the new disc?

 

[Hank 911]

Re: Fuel Pump Rebuild Questions

Don't want to get you side tracked, but how did the water pump thread end? Very good reading. Thanks...Hank

 

[Elmer Fudge]

Re: Fuel Pump Rebuild Questions

Posted by Fishallot,<br />

So what your saying is that the new plastic disc was suppossed to only replace the old small plastic disc not the rubber check valve too? I'm supposed to still have the old rubber check valve under the new disc? <br />---------------------------------------------------------------<br /> <br />As far as i 'm aware that's right,someone will come along and correct me if i'm wrong.

 

[Fishallot]

Re: Fuel Pump Rebuild Questions

Geeeeez.... I screwed this one up. I didn't re-install the rubber check valves. To make matters worse I threw them away and the trash man has already been by. I hope I can buy the rubber check valves as seperate parts. <br /><br />Does anyone have any info on the 2 oil holes in the boost diaphram? My Clymer manual mentions them but the old part and the new one didn't have the 2 oil holes in it.<br /><br />The water pump dilema isn't over yet. I'm going to give it one more try before turning it over to a pro.

 

[outboardguy]

Re: Fuel Pump Rebuild Questions

I don't think the rubber check valves are supposed to be reinstalled.I believe that Mercury updated the check valves to be straight plastic because of all the alcohol that is in today's fuel.Previously the alcohol would make the rubber detriorate very quickly.I sure hope I'm remembering right, but some one will contradict me if I'm wrong.

 

[rodbolt]

Re: Fuel Pump Rebuild Questions

hello<br /> what outboardguy said<br /> dont reuse the rubbers<br /> merc updated that. just use the disc, the oil hole thing is a different animal. someplace there is a bulliten on it. if it worked well with the solid diaphram then put the sme back in it. if it had the one with oil holes then use that one.<br /> good luck and keep posting

 

[Fishallot]

Re: Fuel Pump Rebuild Questions

Thanks for the replies guys. I had told myself that if I screwed this one up my outboard repair days were over. <br /><br />As for the 2 oil holes in the diaphram, it bothers me that the manual says they should be there but they aren't. I'm sure the rebuild kit that I installed was the correct one for my motor as I'm buying my parts from the best Merc parts dealer in town. I know that oil is mixing with the gas without the 2 holes as I can see it burning in the exhaust and the oil level is going down in my tank. If someone could assure me that this motor doesn't require the diaphram with 2 oil holes it sure would ease my worries.<br /><br />Thanks again for all the help.