Johnson 90hp 1988 removing VRO

[619clippers]

just wondering if anybody new what fuel pump to replace the existing vro system. What would be the model number of the fuel pump to replace the VRO

 

[ezeke]

Re: Johnson 90hp 1988 removing VRO

If your existing VRO pump has four wires in the harness, you will need #5007420.
If your existing pump has a three wire harness you will need pump kit #5007423 and #0174710.
You can also use a pre-mix pump #5007422 and eliminate the oil tank.

There are many older VRO/Pumps in stock around the country which may provide less than desirable service; it would be better to buy the newer parts from a known reliable source: http://continuouswave.com/ubb/Forum3/HTML/013127.html

 

[bkwapisz]

Re: Johnson 90hp 1988 removing VRO

If you're deleting the oil tank and going to premix you'll need to make an adapter plate and get a premix pump like ezeke suggested. I used one like this:

http://cgi.ebay.com/ebaymotors/John...6093991QQptZBoatQ5fPartsQ5fAccessoriesQ5fGear

And my boat never worked better.

 

[Haffiman]

Re: Johnson 90hp 1988 removing VRO

If you mean by 'replace' that you want to pre-mix in the tank, you disconnect the oil-hose from pump, plug the oil in on pump with a piece of hose and screw.
Pull apart the wire connector going from VRO to engine harness, disconnect the oil-tank alarm.
Then you may use your old pump, or any any other VRO pump that has been used on a 70 HP and up.
You may even buy the small pump used on the pre-VRO V4 engines.
The most expensive solution is to by a new VRO pump with or without the oil-pump/sensor part.

 

[ezeke]

Re: Johnson 90hp 1988 removing VRO

If you want to "replace the system" you will want to use the OMS pump.

If you want to go to pre-mix and eliminate the oil tank, then yes, you could use the conventional lift pump as shown on the 1990 88HP models. You don't need a bracket with the correct pump #433387; it screws directly onto the engine, eliminating the third hose. http://shop2.evinrude.com/Index.aspx?s1=75ef30c9babaa8aa7d8f0a13ea960ec4&catalog_id=0&siteid=1

 

[619clippers]

Re: Johnson 90hp 1988 removing VRO

ezeke,
thanks for the help, i am a bit confussed pn#433387 is now 438556. is ther supposed to be tree nipples on this pump?

 

[ezeke]

Re: Johnson 90hp 1988 removing VRO

Pump #0433387 had two nipples because it screws directly to the engine and takes its pulse through a hole in the back of the pump. Other pumps with the same configuration had different sized nipples, so it depends on the hose on your engine. 0438556 has the replaceable hose fitting so it superseded both 0398387 and 0433387.

 

[619clippers]

Re: Johnson 90hp 1988 removing VRO

Thanks for all the info, pump installed engine runs better then ever! Can you tell me what wires to disconnect from the old vro. there are four wires, should I follow them and remove?

 

[ezeke]

Re: Johnson 90hp 1988 removing VRO

There should be an amphenol plug at the end of the four wires; disconnect that.

 

[619clippers]

1988 Johnson 90hp Dual Carb Orifice's

1988 Johnson 90hp Dual Carb Orifice's

Top Carb has two 26c orifice's in the float chamber and lead shot plug in the carb body.

Bottom carb has two 56c orifice's in the float chamber and lead shot plug in the carb body. is this a correct set up? motor has problems ideling and kinda spudders at WOT.

 

[Haffiman]

Re: Johnson 90hp 1988 removing VRO

Go to the parts catalog at boats.net.
There you will find the correct orifices and location of the different ones concerning your engine.
On your engine both carbs are identical in orifice setting.

 

[619clippers]

Re: Johnson 90hp 1988 removing VRO

OK,

In my book it states that in the float chamber it requires two "high speed" orfices are those the 56c or the 25c, 25c being the tiny opening. And whats up with the lead shot?????????????

 

[Haffiman]

Re: Johnson 90hp 1988 removing VRO

Each of the carbs are in fact two separate carbs, they just share the float chamber.
The float chambers have 2 x 56C as high speed jets and 2 x 26 as intermediate.
In the upper carb body you have the idle air correction jet No 34.
The lead shot is a plug needed after machining. If missing or leaking, you get false air!!

 

[619clippers]

Re: Johnson 90hp 1988 removing VRO

each carb has its own float chamber, 4 orfices in each carb, two in the float chamber two behind the lead shot. My carbs have small 26c's in the float chamber on the top carb and two 56c in the bottom float chamber, dont know whats behind the lead shot. scared to remove? Motor has trouble idling.

 

[Haffiman]

Re: Johnson 90hp 1988 removing VRO

Your engine has 4 cylinders, in principle 4 individual carbs, but two and two 'built' together sharing one float chamber!!
Nothing behind the lead shots but a channel, leave them!!
If idle problems, carbs cleaned, cooling system with thermostats working, spark on all cylinders, do a compression test!

 

[619clippers]

Re: Johnson 90hp 1988 removing VRO

Did a Compresion test. 105 on each cyn. maybe I did it wrong, what is the proccess of a comp test in your opinion.

 

[Haffiman]

Re: Johnson 90hp 1988 removing VRO

Run test both at cold and warm engine.
Spark plugs removed, emergency stop not hooked on, throttle in WOT (carbs fully open).

 

[619clippers]

Re: Johnson 90hp 1988 removing VRO

No amphenol plug, all four wires lead to a 7 or 8 peg post on port side of motor, any suggestions, also thanks for all the top notch advice!