Rebuilt Fuel pump Failure

[DDorriety]

I have a 150hp Mercury Salt Water Series motor. It is the same power head as the XR6. I recently replaced all the hoses, primer bulb, fuel filter, anti siphon valve and installed a Sierra diaphragm kit in the fuel pump. I took the boat out for a test run, it started fine I ran the boat at half throttle for about five minutes. I then decided to take it WOT, she went to 5200rpm no problem for about 15~20 seconds then stared stumbling. I limped back to the landing
and took the boat back home. I removed the fuel pump and with a quick test
by blowing and sucking on both the inlet port as well as the outlet port realized neither of the internal check valves were sealing off. Upon dissembling the pump I could find no problem with the pump assembly.
I then placed the little plastic check valve disk on a CD to check for flatness, as I expected the disk were slightly warped. I would guess it was about a 0.010" warp. I cannot imagine what would cause this failure.
Would any of you guys have any ideas what would have caused the check valves to fail?

I should mention I replaced the aluminum 1/4" anti siphon valve with a 3\8"
brass valve. This larger valve may have a stronger spring I don't know. My thinking even if it does have a stronger spring it should not cause a valve failure.

Any help would be appreciated.

Dennis

 

[DDorriety]

Re: Rebuilt Fuel pump Failure

Could This have been a bad kit?

 

[sschefer]

Re: Rebuilt Fuel pump Failure

Is the anti-siphon valve your talking about the one between the pump and the oil tank? It's a checkvalve to keep fuel from pumping back into the oil tank. It needs to be the correct size but I don't think it's your problem either.

The plastic disc's are accompanied by a rubber disc. The rubber disk goes on first then the plastic. The amount of warpage you describe won't cause your problem. I had a couple of Sierra kits come without the rubber disc's. I called the re-seller and they replaced the kits. I think that's where your problem is.

 

[DDorriety]

Re: Rebuilt Fuel pump Failure

Thank you for your response!

The Anti siphon valve I am talking about is the one on the fuel tank.
This valve is there for safety in case a line breaks to prevent fuel from siphoning from the tank into the bilge.
I have purchased a Quick Silver Diaphragm kit and replaced the Serria kit.
The Quick Silver kit did not have the rubber pieces you mentioned.

The original pump did not have any rubber pieces either.
I attached a drawing of my pump. The disk I am speaking of is #2 on the attached drawing, this disk seats directly on the metal. If these disk seat on a rubber surface they would be much more forgiving.

I am concerned I will have another failure, maybe in the gulf next time.


Any ideas would be appricated.

 

[wtwe2step]

Re: Rebuilt Fuel pump Failure

I rebuilt mine last year with merc parts and the old one (1990) had the rubber and the new one did not. The new instructions did not mention the rubber either. After rebuilding, it has run fine for months.

 

[DDorriety]

Re: Rebuilt Fuel pump Failure

I look back at the instructions that came with mine. It stated;

"When replacing the rubber check valve retainer with nylon check valve retainer,retainer holes must be enlarged to .125 in. diameter and hole edges chamfered."

So it look like this was a design change.

I puzzled as to the root cause of failure????????

 

[Barnacle_Bill]

Re: Rebuilt Fuel pump Failure

The older check valve with rubber on them was replaced due to them curling up caused by E-10 gas. They were replaced with plastic type. See Merc's info advisory 2001-17

 

[j_martin]

Re: Rebuilt Fuel pump Failure

I use the genuine Mercury kits. They have only the plastic disk in it. First time from rubber you need to fix the holes per the instructions. Setting the rivet properly has a learning curve.

If it was loose, I suspect the rivet was not seated tightly.

Get a Mercury kit and install it carefully, and you're good to go.

hope it helps
John

 

[DDorriety]

Re: Rebuilt Fuel pump Failure

Thanks for you replies!

I have replaced the Serria kit with a Quick Silver kit.
I am under the impression that Quick Silver parts are genuine mercury parts.
Is this correct? If so maybe I'm good to go.

Thanks again,
Dennis

 

[wtwe2step]

Re: Rebuilt Fuel pump Failure

Yes Quick Silver parts are genuine mercury parts

 

[Faztbullet]

Re: Rebuilt Fuel pump Failure

You will notice that the plastic disc's in Merc kit is also bowed slightly and marked with a blue stripe and blue stripe goes up.

 

[sschefer]

Re: Rebuilt Fuel pump Failure

The older check valve with rubber on them was replaced due to them curling up caused by E-10 gas. They were replaced with plastic type. See Merc's info advisory 2001-17

LOL too funny, I've been hording the rubber disks.... I just went back through the service advisories and there it was.. I guess I've been runnin electrics too long.

 

[DDorriety]

Re: Rebuilt Fuel pump Failure

Thanks for the replies!

I still had the Serria disk. I took another look at them. They did not have any
Identifying marks. I also reviewed the instructions that came with the Quick Silver kit. The instructions did not mention the blue line or orientation of the disk. Maybe this is another change at least I hope so I did not see any orientation marks and I have them installed.