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johnson 120 VRO 88, Idle issue? Running Rich? Stalling

Rickstar

New member
Hey, I recently just brought a boat with a Johnson 120 VRO 88 and at on the second outing it doesn’t start or idle well. It has plenty of crank from 2 batteries and it took approximately 7 times of turning it over once or twice using key choke and then getting the idle lever going. When it does start it blows a load of white smoke and once it gets going it’s fine (although I was surprised at how much fuel we got through)
After a 20min run in the ocean at 3/4 throttle I brought her back to idle to berth and she kept stalling.
I managed to find the primer solenoid which was clicking when I press the primer key in, so presume the choke is not getting stuck on?
I am wondering how to alter the idle? Theres a couple of screws somewhere which I need to adjust? I cannot seem to locate them.
Which part adjusts the fuel, I have a feeling it is running too rich, which could be why it is stalling.Thanks I’m advance Cheers Ricky
 
You could possibly have a failing vro pump. Meaning that your pump could be applying more oil than needed. Pull one carb and check if float bowl has alot of oil in it. If yes look into a new vro or pick up non-vro fuel pump. If it not filled with oil, then compression test and/or visual inspection of pistons (use of borescope) . If no damage to compression is seen/found look to ignition system break down or overheating at lower speeds.
 
Ok thanks I will book in compression test. Is it worth having a play around with the idle screws? Can you direct me to these two screws that can be adjusted.
Also, what could be making it run rich, and how can I verify? I feel like it is getting flooded on start up.

Struggling to upload pictures this thread? I click on upload and nothing happens?
 
Sounds like it is flooded with water. A flooded motor will spit blue or black smoke out not white.

That has not been my experience!... A fine spray of water entering a cylinder will most definitely show up as white smoke. Excessive fuel/oil will show up with a heavily colored smoke effect, usually blue, and a flooded engine puts out nothing as it is not running!
 
I dont believe it has idle adjustment screws. I have a 1990 90 hp, and mine definitely does not. You can look at diagrams here on the parts side of this website to confirm.
On starting, pump fuel bulb til firm, then have the warm up lever pulled way up, then push in on the key to activate primer for a couple of seconds, then turn key to crank. You may need to hold the key in for a second or two it til motor revs up. Lower warm up lever completely before putting into gear.
Definitely do a compression and spark air-gap test. If each cylinder has good compression and a strong spark that can jump a 1/2" gap, then look at fuel. Make sure all the lines are good and tight and bulb functions correctly ( pumps up hard and stays that way until motor is running). Clean the carbs, including running wire through each jet. While you have the bowls off, lay them on a piece of glass to see if they have warped. They may be letting air in. (This was my last issue). They can be sanded down flat or replaced.
 
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