VRO Failure & Life Expectancy

[Terrapin]

The VRO pump, on my 1986 Johnson 150 (J150TXCDC), failed after only three summers (15 months) of use. While trolling, the engine stalled and I had to use the primer bulb to fill the float bowls. The engine would not continue running unless I actuated the primer bulb. Experiencing this years ago, I diagnosed the problem as a fuel pump diaphragm failure. I called it a day and asked my crew member to man the primer bulb for the short trip home. Immediately, upon accelerating the No Oil Alarm sounded. I shut it down and was towed back home. My diagnosis changed to the failure being on the air pump diaphragm side since I lost both fuel and oil delivery. I plan on replacing the VRO pump with a new OEM p/n 5007423 and will then consider rebuilding the current VRO pump for use as a spare.
Any thoughts on why this failed after only three summers of use? My previous VRO pumps had the following life:
2003 (boat purchase) to 2008: 5 years of service minimum. Root Cause of Failure was the fuel side diaphragm
2008 (end of season) to 2020: 12 years of service. Replaced as preventive maintenance at rebuild
2021 engine rebuild and VRO pump replacement to current date: 3 years of service

 

[tphoyt]

I vote for poor quality materials and fuel.
Things just aren’t what they used to be.
Every company is looking to save a few bucks at the consumers cost.

 

[dingbat]

1996 Ocean Pro - 200
Rebuilt 1997 OE pump in 2005 on a misdiagnosis. Rebuild went 6 months. Replaced with new OE pump.

Pump reused in 2011 short block rebuild and is currently in use.

Nothing but E-10 since area mandate in 1999/2000

Have you checked on the vacuum side (tank to pump) for a flow restriction?

 

[Terrapin]

1996 Ocean Pro - 200
Rebuilt 1997 OE pump in 2005 on a misdiagnosis. Rebuild went 6 months. Replaced with new OE pump.

Pump reused in 2011 short block rebuild and is currently in use.

Nothing but E-10 since area mandate in 1999/2000

Have you checked on the vacuum side (tank to pump) for a flow restriction?

I don't have an anti-siphon valve on the fuel tank (63 gallon) or a filter screen/sock on the pick-up. I have always had a Racor fuel and water separator (S3227, 10 micron) in line and I replaced all the fuel lines in 2006 ish. I did add a fuel flow meter in early 2020. Is there a vacuum test I could perform at the engine to ensure I am not exceeding a maximum?

 

[flyingscott]

Where did you get the rebuild kit from? Was it a Chinese kit?

 

[dingbat]

I don't have an anti-siphon valve on the fuel tank (63 gallon) or a filter screen/sock on the pick-up. I have always had a Racor fuel and water separator (S3227, 10 micron) in line and I replaced all the fuel lines in 2006 ish. I did add a fuel flow meter in early 2020. Is there a vacuum test I could perform at the engine to ensure I am not exceeding a maximum?

Same filter configuration here but added fuel flow and related in-line 30 micron filter in 2008 or so.

It's my understanding the vacuum switch (fuel restriction) triggers at 7-inches-Hg but no idea what "normal" would be.

I'm seeing reference to less than 4-inches-Hg but have no official validation to that figure

https://www.amazon.com/Spectre-Performance-59013-Pressure-Fitting/dp/B000BPZ4SW/ref=mp_s_a_1_3?keywords=inline+fuel+pressure+gauge&qid=1692660981&sr=8-3

 

[Terrapin]

Where did you get the rebuild kit from? Was it a Chinese kit?

After rebuilding my own engine with the help of the experts on this site, I would never purchase anything but OEM. The above mentioned VRO replacements were complete units (not rebuilds). I do plan on troubleshooting the current bad unit (off the engine) and using a rebuild kit from Mastertech Marine in Milton, Florida. These rebuild kit components are advertised as OEM.

 

[Terrapin]

Same filter configuration here but added fuel flow and related in-line 30 micron filter in 2008 or so.

It's my understanding the vacuum switch (fuel restriction) triggers at 7-inches-Hg but no idea what "normal" would be.

I'm seeing reference to less than 4-inches-Hg but have no official validation to that figure

https://www.amazon.com/Spectre-Performance-59013-Pressure-Fitting/dp/B000BPZ4SW/ref=mp_s_a_1_3?keywords=inline+fuel+pressure+gauge&qid=1692660981&sr=8-3

If I can easily hook up my MityVac downstream of the primer bulb, I will see what vacuum pressure is required to pull the fuel. I will mention that my fuel restriction alarm does function because I can kink the fuel line hose going into the engine and the alarm horn will sound continuously until the kink is removed. Given that is the case, it may not be a fuel line restriction.

 

[dingbat]

If I can easily hook up my MityVac downstream of the primer bulb, I will see what vacuum pressure is required to pull the fuel. I will mention that my fuel restriction alarm does function because I can kink the fuel line hose going into the engine and the alarm horn will sound continuously until the kink is removed. Given that is the case, it may not be a fuel line restriction.

It may not be a fuel restriction but your only guessing until proven otherwise

If "working" vacuum is 3Hg and you're pulling 6Hg, the pump is working twice as hard yet under the 7 Hg alarm.

Question becomes... does working at double the design over designpressure relate to a 50% reduction in service life?

FWIW: May want to replace those 2006 fuel lines again. Its been 18 years

 

[tphoyt]

You raise a really good question Flyingscott.
I have purchased stuff from master tec and have always had a great experience.

 

[dingbat]

It may not be a fuel restriction but your only guessing until proven otherwise

If "working" vacuum is 3Hg and you're pulling 6Hg, the pump is working twice as hard yet under the 7 Hg alarm.

Question becomes... does working at double the design over designpressure relate to a 50% reduction in service life?

FWIW: May want to replace those 2006 fuel lines again. Its been 18 years

Factory Manual:
1 to 4 Hg with no bubbles.
Bubbles or in excess of 4Hg requires further testing

Cavitation (air) could play a role as well.

 

[flyingscott]

You raise a really good question Flyingscott.
I have purchased stuff from master tec and have always had a great experience.

I trust Master tech. Last time I checked they were out of stock. Good to know they have some.

 

[flyingscott]

After rebuilding my own engine with the help of the experts on this site, I would never purchase anything but OEM. The above mentioned VRO replacements were complete units (not rebuilds). I do plan on troubleshooting the current bad unit (off the engine) and using a rebuild kit from Mastertech Marine in Milton, Florida. These rebuild kit components are advertised as OEM.

One question did you replace the pulse limiter with a new one? A bad pulse limiter will shorten the life significantly.

 

[Terrapin]

Factory Manual:
1 to 4 Hg with no bubbles.
Bubbles or in excess of 4Hg requires further testing

Cavitation (air) could play a role as well.

Thanks for this info, I will try and attach my MityVac to get a fuel draw vacuum reading.

 

[Terrapin]

One question did you replace the pulse limiter with a new one? A bad pulse limiter will shorten the life significantly.

Yes, I was thinking of skipping pulse limiter replacement with this new one, but with your information I'll replace the old one with the new one enclosed in the VRO fuel pump kit.

 

[racerone]

The pulse limiter is nothing but a ---" flow fuse " ----To protect the VRO from a high pressure/ airflow event.---It closes in the event of high airflow to the VRO.------The housings on the VRO would explode if subjected to too much pressure.

 

[Terrapin]

The pulse limiter is nothing but a ---" flow fuse " ----To protect the VRO from a high pressure/ airflow event.---It closes in the event of high airflow to the VRO.------The housings on the VRO would explode if subjected to too much pressure.

Got it! Thanks racerone.
Do you see these VRO's fail so quickly? In my case three years (15 total months of run time).

 

[racerone]

No----I do not see rapid failure.-----I would say you need to look for other issues in your fuel system.-----To long a fuel line.----Too many filters.-----Plugged pick up tube in tank .----Low crankcase compression etc.

 

[guy48065]

Consider vro delete?

 

[Chris1956]

I still have the original OMS pump on my '98 Johnny 150HPV6. I do carry a gal of 2 cycle oil with me at all times. Should the OMS fail, I can dump the correct amount of oil (or thereabouts) to make a 50::1 fuel mix in the 63Gal fuel tank. I would need to spend some time rocking the boat to mix it, though. It would also be a good idea to d/c the fuel line and pump primer until you see the dye in the 2 cycle oil come thru.