replace vro fuel pump

J

johnson89

Petty Officer 1st Class
Joined
Apr 4, 2010
Messages
244
I have a 90hp 1989 johnson and am 99% sure the fuel pump is getting week, motor run great but at idle it sometimes shuts down an primer builb will be soft,other times at high rpm it will start to surge up an down then start running good again, fuel pump is old....no way can I spend the 300- 400 for a new pump.I have looked at some of the standard pumps(non vro) an hope I can replace it with one of these.If so how do these hook up,I notice some have 2 lines an others have 3 lines.Do the 2 lines hook up too fuel in an fuel out an the back of the pump hook too motor for pulse..an the 3 line is fuel in and out an the 3rd line hooks too the pulse connection...IF this is correct which is the best way to go,looks like the 3 line would be easy too hook up...thanks for any help..... yes the motor has great compression, all new fuel line, carbs have been rebuilt, new primer bulb, check valve works fine, no leaks that I can see
 
Mark42

Mark42

Fleet Admiral
Joined
Oct 8, 2003
Messages
9,334
Re: replace vro fuel pump

In 1998 there was an "88 special" model that uses the basic fuel pump. I believe that pump will bolt on in place of the VRO. The wire harness is left unconnected, and remove the oil line and tank.

Double check that the 88 special pump will fit the 90. Its a good way to go, but you do have to pre-mix the fuel.

Another option is to buy the rebuild kit for the VRO. If the VRO gave many years of good service, it might be the best way to go.
 
S

seahorse5

Rear Admiral
Joined
Jan 24, 2002
Messages
4,698
Re: replace vro fuel pump

Your best bet would be to troubleshoot the fuel system per the manual, using a pressure gauge for the pump output and a vacuum gauge with clear line for the input to the pump. That way you would rule out a fuel delivery problem, which could give you the very same symptoms.
 
C

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
28,119
Re: replace vro fuel pump

OK, if the primer bulb goes soft, the fuel pump is doing it's job, and there is a fuel restriction between the primer bulb and the fuel tank. It could be the antisiphon valve, fuel pickup screen, tank vent, fuel filter or fuel lines.

So much for the 99% confidence....

Check this out before you blame the fuel pump.
 
J

johnson89

Petty Officer 1st Class
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Apr 4, 2010
Messages
244
Re: replace vro fuel pump

I have all new fuel line,I had the antisiphon valve out an looks fine, ball move free, the pick up tube is in good shape(checked for leaks) an the filter screen on it is clean.Its has a built in tank an the fuel vent is clear, you can blow air into tank an it comes out vent.Whem the primer bulb goes soft you can pump it back up an motor will run fine.Only seem to have a problem sometimes at idle or high speed, acts like its running out of fuel.Fuel flows thru the filter with ease, it has been clean out. fuel pump is 22 years old
 
R

Rick.

Captain
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Jul 30, 2006
Messages
3,740
Re: replace vro fuel pump

If it was a weak pump it would giving you poor idle and high speed it would most likely give poor mid range as well. If pumping your bulb helps at high speed only then I would be more certain about the pump being the problem. I would suggest carbs. may need cleaning and then a linc and sync. Fuel pump is old but not that old. If your inclined to get rid of the VRO then go for it but I just doubt that will be the end of your problem. Best of luck. Rick.
 
J

johnson89

Petty Officer 1st Class
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Apr 4, 2010
Messages
244
Re: replace vro fuel pump

the link and sync was done about 2 months ago, it idles around 850 but sometimes runs out of gas, then repump the bulb an it is fine.The carbs were rebuilt 3 -4 months ago.I am in my boat 99% by myself,so hard too try to pump primer bulb when it starts surging, but only does this maybe 1 or 2 times throuhout the day.Might an see if I can get a pressure gauge for the pump.The carbs seems to be preforming well, will get on plane in about 3 sec. an motor will run pass 5700rpm but I back off.14x19 prop, 16' boat.
 
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,119
Re: replace vro fuel pump

OK, How about an air leak in the fuel line or fittings (including fuel filter) between the primer bulb and the engine. That would cause the engine to run out of fuel, especially at slow speeds.
 
N

noelm

Senior Chief Petty Officer
Joined
Mar 8, 2005
Messages
761
Re: replace vro fuel pump

the first and probably the simplest test is borrow/buy a new remote tank, complete with new hose and bulb, and run the motor with it, I think you are chasing something major that is not the problem. You suspect the fuel pump, but need to listen to advice rather than close your eyes to help becuse you have "fuel pump" in your mind!
 
J

johnson89

Petty Officer 1st Class
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Apr 4, 2010
Messages
244
Re: replace vro fuel pump

well the cost to get a new fuel line an primer bulb an test gauge for the fuel pump, thats 22 years old or get a brand new fuel pump for 43.00 or went ahead an got the new pump.So I decided to tear apart the vro pump an here are the pics. does not look good...When I install the bew pump(non vro) does it matter which way the lines goes.It would go a lot better to have the lines come from the top, or do I have too have the lines go out the bottom an readjust the manifold an turn it over...Also what size plug do I need for the pulse limiter hole...thanks for any help...new pump should be here sat. or monday...even if this does not fix the problem this pump was in need of being change out.
 

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Silvertip

Silvertip

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Re: replace vro fuel pump

There is a difference between a primer bulb going "soft" and one that is being "sucked flat". Any primer bulb will go soft after the engine starts because fuel is being sucked through it. The fuel system between the tank and the pump is not under pressure -- it is under very slight vaccum. So a "soft bulb" is normal. If the bulb is being sucked flat, then there is a restriction between the bulb and bottom of the pickup in the tank. If squeezing the bulb when the engine begins to die helps pick it back up, then there is likely a weak pump or a carb issue (assuming there is not an overheat or oil related issue going on).
 
B

bob johnson

Rear Admiral
Joined
Feb 25, 2009
Messages
4,306
Re: replace vro fuel pump

I am going through some fuel delivery issues as well...I may have a strain on my system. my issues are not shutting me down, but reguire frequent trips to the rear primer bulb to keep the motor from acting like it is going to die or die( starved for fuel)

my gas tanks are 15 feet from my motor, i have 2 port and starboard...both portable with a quick disconnect, so i can pull them out and fill them and maintain them. both lines go to a diverter valve then to a fuel seperator and then an inline fuel filter, then to the motor. i have a primer bulb at each tank and one right before the line goes into the motor.

It seemed i used to only need to prime with the rear primer to run my motor...lately the motor wants to die out in a minute or less from the ramp unless i go back and squeeze the rear bulb again.. this may happen 3 or 4 times and then all seems well

i discovered that if i squeeze the primer by the tank and PUSH the gas all the way to the back... i dont have the issue much if at all


so i suspect I may have an air leak in the front half of the boat...because the motor pulls all the gas up to the air leak.and then dies.

i think once i get a solid colum of gas pushed from the front...the syphon effect holds better and i maintain a solid column of gas.... and when I stop for a while, it lets the air leak in...

just a guess


i was also told my system may be putting a strain on my fuel pump?? is that possible

1996 ocean runner 115 60 degree looper with oil pump discconected

I have a new seperator filter to install and a new quick disconnect to install. and Ill check all my connections again


bob
 
J

johnson89

Petty Officer 1st Class
Joined
Apr 4, 2010
Messages
244
Re: replace vro fuel pump

no the primer bulb is not beibg sucked dry,but when the motor dies you have to do a lot of pumping to get it firm again.I took the gas line off an put it in a gallon jug an pumped the primer bulb an got a good steady flow of fuel,I don't see any leaks any where(everything is new).I notice the part of the fuel pump that moves up and down you can see light thru it in 4 diffrent places so the rubber part is warn pretty good, no tears but not solid.The oil side of this pump had be disconncted 4 months ago.It has a new water pump and yes the overheat alarm does work ,been tested...
 
K

kjdunne

Petty Officer 1st Class
Joined
Sep 22, 2007
Messages
370
Re: replace vro fuel pump

Johnson89, did the new pump you installed match up with your existing hoses and manifold, or did you need to replace / reconfigure them? How about mounting the pump? Which part # pump did you use? Thanks.
 
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