Johnson 50HP VRO fuel issues

[kcoleman10]

I got a 1996 Johnson 50HP with the VRO setup. The problem I'm experiencing appears to be lack of fuel. I pump the inline fuel bulb, fire motor up and it runs good for about 30 seconds on fast idle. It won't run on just regular idle. After 30 seconds it will stall out. But if I pump primer bulb while its running every 5 seconds or so I can manage to keep it running. I don't believe its an issue with carbs as I just tore them apart and cleaned them. My fuel hose and primer bulb is new. The only other issue noticed is that after 10-15 seconds the alarm buzzer starts beeping. It's pumping water out the pisser hose very strong so I'm assuming its an oil alarm. I'm considering doing away with VRO pump and installing a normal fuel pump. Any help with this would be appreciated and if someone has already installed an aftermarket fuel pump, what kind did you use and how did you hook up fuel lines. Thank you.

 

[fixitsb1]

Re: Johnson 50HP VRO fuel issues

The VRO pump (varible ratio oiler) on these models was a good concept but they are diaphram pumps and over time begin to leak. sucking air, loosing the vacume required to pull the fuel from tank to carbs. In the shop manuals their are steps to
determine if the VRO pump is defective (leaking). My suggestion to you is remove VRO pump and replace it with regular fuel pump and go back to mixing oil and gas 50 to 1 ratio. This
fix will probably be less expensive too!

 

[ANGEL-1]

Re: Johnson 50HP VRO fuel issues

well pal you and I think alike. I have lost all confidence in my VRO on a 2000 50 Johnson so I am currently in the middle of installing a new pump and rebuilding the carbs. I based my decision on removing the VRO after reviewing the shop manual and realizing there are just too many possible scources of problems with these pumps and the parts are not cheap. Bill at Mastertech Marine (www.maxrules.com) directed me to the least expensive conventional diaphram pump (#8556 by Sierra $64) check with him on-line to be sure you get the right pump and if you ask he includes the mount screws. . The first issue was removing the pulse limiter which is threaded into the cylinder head. Put a 7/8" wrench on the plug endwise and turn the wrench with a 2nd wrench. I had to do this due to the lack of space for a socket or normal approach with a wrench. I installed a Gates auto type 1/8-27 brass pipe plug with some sealant but I was having trouble getting it started so I used a 1/8 -27 NPT pipe tap (buy at your local NAPA dealer), loaded the flutes with grease (to capture the metal) and ran the tap until it started to tighten up and then add 2 more turns, which is increasing the diameter of your tap (a pipe tap gets large as you thread it in). I did this 2 or 3 times until I was just able to get the brass plug started. The new fuel pump mounts on the port side where I have 3 holes. The middle hole had a gasketed plug in it but once removed this becomes the fuel pump pulse. I installed new fuel lines and will route the pump out line to the old 3-finger fuel manifold which distributes fuel via 5/32 lines to the carbs and primer on my motor. Even if I continue to have motor problems after completing this project, I am still happy that I have eliminated the possibility and constant concern if the VRO is working properly. Now all I have to do is remember to pre-mix the 50:1. I am still in the middle of rebuilding the carbs so I don't know the outcome yet. I am reasonably mechanical but this is all new to me so I am going slow and checking references. I suggest you confirm with others that I am on the right track here. Best of luck.

 

[Chris1956]

Re: Johnson 50HP VRO fuel issues

Gee, Te OMS pump on my '98 Johnny 150HPV6 works perfectly, and has never given me an ounce (or 16oz/6gal) of trouble. It is very convenient.

I do carry a gal of 2 cycle oil, in case I get the dreaded "no Oil" alarm. I can dump it into the fuel tank, give the boat a shake and away we go...

 

[boobie]

Re: Johnson 50HP VRO fuel issues

What if it stops pumping fuel rather than oil?? Then what??

 

[rolmops]

Re: Johnson 50HP VRO fuel issues

Then you should pull the old oars out and paddle back to shore

 

[boobie]

Re: Johnson 50HP VRO fuel issues

Sea Tow? That's eaisier. LOL.

 

[kcoleman10]

Re: Johnson 50HP VRO fuel issues

Where can I look for the problem here...I'd like to try and fix it first before having to remove it all and do a conventional pump. Maybe a vacuum line of some sort or something? Any help would be appreciated.

 

[Chris1956]

Re: Johnson 50HP VRO fuel issues

There is a pulse line that powers the pump, from the block. There also may be a pulse limiter, which can get dirty. I would check/clean the pulse limiter and inspect the pulse hose before I replaced anything. There is a fuel side rebuild kits for that VRO pump. The kit number will be in the OMC Accessories catelog.

 

[kcoleman10]

Re: Johnson 50HP VRO fuel issues

Where would the pulse limiter be if there was one? I will check hose that goes from VRO back to the block that creates the vacuum.

 

[kcoleman10]

Re: Johnson 50HP VRO fuel issues

View attachment 120025

Timeout...I may have lines mixed up. I have hose 12 coming out to cowling and oil hooked up to it. Then hose 21 with the plastic elbow (no. 8) I have going straight back to the block to the nipple that the hose fits on there. According to the drawing hose 12 should be the pulse line.

 

[Chris1956]

Re: Johnson 50HP VRO fuel issues

I cannot see your drawing. You can maybe figure it out by looking at figures on crowleymarine.com website. On that website for your model, I think hose part# 21 is for gasoline, and hose part# 8 is oil line. Pulse line is hose part #18