1985 johnson 90 horse vro fuel problems

[markusguitar]

I have a 90 horse johnson that i bought from a neighbor , the motor had been sitting up for some time . Had a new water pump installed and the carbs cleaned. The motor ran like a new one , the only problem was an alarm about half throttle . I took it back and they supposely fixed the alarm only thing it woulnt run well at all . It was hard to start wouldnt idle . The repair shop told me to keep the choke pushed in that help some the motor would smooth out some but go back to the original state . Took it back told them the problem and either they have done something that cant be fixed , or is too expensive to fix and wont own up to it , i think its the vro wich is 500.00 dollars for a new one , please advise

 

[cfauvel]

an alarm that comes up at half throttle sounds like fuel obstruction, BUT this motor shouldn't have the vacuum switch that would sound the alarm.

there is a host of things that could be the problem....but to be clear the issue is that it is hard to start and doesn't idle well?

1 - double check the primer solenoid woks.

a - disconnect the tiny hoses coming from the solenoid and pump primer bulb hard ....check for NO fuel coming out of the two tiny nipples.
b - with primer bulb pumped hard....turn key on, push key into activate solenoid....verify that fuel DOES come out of solenoid.​

2 double check that ALL butterflies of the carbs are fully closed at idle , if not , if just ONE butterfly is slightly open it isn't going to idle right.

a - if not fully closed you'll have to do a link/synch procedure for your model motor.​

3 - test the functionality of the fuel pump.

a - hook up a TEE at the fuel inlet and attach a vacuum pump/gauge....when you get the motor running the pump should draw 3inhg at idle...if more than 5 inhg, you have a fuel obstruction before the pump.
b - if you have less 3 inhg, then you may have a pump issue.​

1 - check the pulse limiter is not fouled up (goes between the engine and the air motor inlet on the VRO)
2 - remove VRO from motor....and follow the testing procedures from boatpartstore<DOT>com/vrotable.asp​

4 - Adjust the floats on the carbs according to the service manual...not sure if this motor is plastic carb or metal carb...nor do I know if these carbs have an idle mixture screw....if they do then find out the original number of counterclockwise turns from fully seated and try to start the motor..

to start the motor the steps should be like

1 - pump primer bulb hard
2 - turn key to ON and push in for 5 seconds or so
3 - push throttle to slightly more than 1/4 up (in neutral)
4 - turn key to START whilst holding in key.
5 - once motor is started hold key in until motor starts to die, then let it go. Let it warm up for a minute.​

you may need to push throttle up more than 1/4.

 

[cfauvel]

BTW your year motor does NOT have the most desirable VRO...you may want to consider getting a newer used one from ebay...1999 or newer are good (OMS) and the internals are available still. If not, anything newer than 1990 will get you a VRO2. Look at the part numbers for the fuel pump for the same HP but newer year.

 

[flyingscott]

What does the alarm sound like? There are 3 possible.
​​​​​​One is a solid tone that indicates an overheat problem.
One is a beep every 20-30 seconds that indicates a low oil issue.
Then last one would be a beep every second or 2. That would be a no oil flow warning.
There is no fuel restriction alarm on the v4 motor.
For Cold Starting There Is No Need To Hold The Primer In For 5 Seconds. Just push the Key In and Start the Motor.

 

[racerone]

???----" ran like a new one "----Now it is hard to start ?-----Do a compression test first.

 

[OLDIRON]

I wonder also which alarm he heard. If it was the hot horn, they may have messed with the timing and got too far advanced. That would make it hard to start and overheat. Wouldn't run very good either.

 

[oldboat1]

just an additional thought -- The shop would typically be running on their own fuel. Yours may be contaminated. Try another tank if you can borrow one, or maybe your trolling motor tank. Use fresh fuel with a 50:1 mix.


Particularly if you have a built-in tank, pump some into a glass jar or siphon some up from the lowest point of the tank. Let it settle out and look for water (fuel will float on top).

[Edit. Check/test fuel quality, but strike reference to running test while other testing pending.]