motor will stay running if you constantly prime the bulb

[johnson7o]

I have a 94 johnson 70hp. had the carborators rebuilt and new water pump. I went out on the water to test is ran fine but could no idle in. took it this weekend and had to constantly prime the bulb. It has a vro and the oil light come on as well. Do I have a fuel pump problem or is the vro no working. If its the primer i can replace it and disconnect the oil mixing side and pre-mix myself

 

[James R]

Re: motor will stay running if you constantly prime the bulb

Sounds like the tube from the crank case to the pump is off or leaking. Run on 50:1 until you have solved the problem.

 

[johnson7o]

Re: motor will stay running if you constantly prime the bulb

I'll take the cover off and prime the bulb to see if there is any leaks. thanks

 

[James R]

Re: motor will stay running if you constantly prime the bulb

You have misunderstood. Squeezing the bulb may well show fuel leaks but the tube I refered to provides the impulses that power the VRO, both the fuel and the oil pump.

 

[ADK_Boater]

Re: motor will stay running if you constantly prime the bulb

Also, check your fuel connections. I had a similar problem until I changed the quick-connect male fuel connection that is on the motor. It was an original and a little beat up. I changed the female end on the fuel line too because it was cheap and I wanted to kill two birds with one stone. The o-rings sometimes get damaged and you will not have a good seal. I got the female end at wal-mart for 5 bucks. the male end you can find from 15 - 35 depending on where you get it and if it is used. If your connections look good and you have a good seal, then take apart your fuel pump (put paper towels or a rag under to soak up gas when you take it off the motor), check the diaphragm for tears/holes/perforations. if it is not perfect get a rebuild kit. If it looks good, clean it with soap and water, rinse, and dry. Now put it back together just the way it was. I did this at one point too and it really helped.
James R is right about that crankcase pressure line. Check that first!

 

[freddyray21]

Re: motor will stay running if you constantly prime the bulb

get rid of the vro go to a regular fuel pump and mix your gas.

 

[johnson7o]

Re: motor will stay running if you constantly prime the bulb

How can I find Regular fuel pump. Going to the lake and drag it back to my house to get numbers and work on it at the house.

 

[johnson7o]

Re: motor will stay running if you constantly prime the bulb

Motor number j70tleum. Can't find fuel pump that's not a vro

 

[jadedhart]

Re: motor will stay running if you constantly prime the bulb

i'm having a similar problem with my 99 johnson 115. it starts and stays running as long as i pump the primer bulb. i'm fairly well mechanically inclined but know nothing about marine engines. if i have directions/schematics can probably fix anything. anyone have schematics or know where i can find them?

 

[BassHunter0123]

Re: motor will stay running if you constantly prime the bulb

all these problems sound like bad VRO(fuel) pumps. getting ready to replace mine right now with similar issues

 

[BassHunter0123]

Re: motor will stay running if you constantly prime the bulb

Motor number j70tleum. Can't find fuel pump that's not a vro

you dont need to get one thats not VRO. get the same vro pump and just disable the oil injection and premix your fuel

 

[wilde1j]

Re: motor will stay running if you constantly prime the bulb

Your immediate problem is a fuel delivery problem, which can have a number of causes, such as:
. air leak on pump suction side (bad clamp, cracked hose, cracked tank pickup tube, etc., etc.)
. malfunctioning anti-siphon valve
. plugged tank vent
. trash blocking tank pickup screen
. plugged fuel filter
. collapsed fuel line
. check fuel pump output by taking off outlet hose and cranking engine over (make sure it can't start). You should see long, strong pulses of fuel. If not, pump is bad.

BTW, the gas side of most VRO pumps can be rebuilt, but not the oil side.

 

[lmuss53]

Re: motor will stay running if you constantly prime the bulb

I think this pump will replace the VRO pump, it is a pre VRO, 3 line, (pulse, fuel in, fuel out) pump that was used on 50 to 85 HP motors in the early '70's. The three hose pump is the stock pump on my 1976 55 Johnson.

http://www.boats.net/parts/search/BRP/JOHNSON/1973/50ESL73R/FUEL PUMP/parts.html

Click the part number on the parts layout and see all the different HP models it worked on.

Depending on your motor you may also be able to just mount a standard, non-VRO (88spl, 112sp, 48spl) pump to your block and eliminate the VRO pump. I was able to do that on my 1985 VRO 90 by using the pump off a 90something 88SPL. You must check your VRO motor to see if it has the non-VRO mounting boss and tapped holes, which will be somewhere low on the block, about under the starter.

The only reason I used one of these instead of rebuilding the VRO pump was that it is cheaper.

 

[milliesdad]

i'm having a similar problem with my 99 johnson 115. it starts and stays running as long as i pump the primer bulb. i'm fairly well mechanically inclined but know nothing about marine engines. if i have directions/schematics can probably fix anything. anyone have schematics or know where i can find them?

I got my factory service manual on eBay. Don't remember the cost.

Best advise is to get a manual and start the trouble shooting process.

You can't fix something by throwing parts at it. I learned that at an early age from an old German mechanic that I worked for when I was but a lad.

 

[luckynickles]

Re: motor will stay running if you constantly prime the bulb

check your oil filter on your vro there is a small oil filter on the backside of your oil tank take it offf clean it with gas if that fixes your prob change it