Logo
FULL SITE MENU

Johnson Outboard vro 1987 omc V4

B

badcrank 777

Contributing Member
Hello everyone,

I have a 1987 Johnson 110 HP V4 outboard.

The VRO is working perfect, The carburetors have brand new kit's installed along with new float & needle & seat. The float level is set perfectly as per the service manual. The primer bulb pumps up tite. The reed valves are perfect.

It will start up and idle at 1500 rpm and purr. I can put into gear and plain it out at 5500 run several laps on the lake. But as soon as I idle back down to 1500 rpm, the motor will start to sputter and quit. When I pull the plugs they are soaking wet with fuel/oil mix. It is flooding out. When it starts that sputtering at low idle after running at 5500 RPM I cannot speed back up to clear the fuel in the cylinders, it just dies.

I just don't know what else to do or check, can anyone please help me figure out what is going on with the motor?

Thank you,

Jon
 
You use the term --" perfect "-----I say your compression values are not perfect.----Perhaps try another gage.----Does spark jump a gap of 3/8" or more on all leads ?----And idling at 1500 RPM is too fast !----Checked the flywheel key ?
 
Ok, let me re-check the compression I have a new gauge the kind that you screw the adapter into the spark plug hole.

And I need to clarify the idle, it will idle at 800 RPM, I used the term 1500 RPM as that was the RPM after I slowed down after running across the lake at 5500 RPM with the boat leveled out, and as soon as I slowed down to 1500 or below is when it would start sputtering and die. When I first start the motor I can set at the dock and it will idle for as long as I let it, it is only after running at high RPM and then back down does it flood out, and will not idle. And upon pulling the plugs I find them very wet.

The spark is a bright blue fire ball and jumping 3/8 and more. I only checked one one plug. I will check all four and report the findings.

Raceone, I really appreciate you helping me here. I lost all last summer of boating, trying to get this motor up and running, and working on the boat itself. And finally this summer I have the boat done and the motor running, only to be faced with this issue, and I just don't want to lose another summer.

I will have the readings later today. Is there any special way to check the compression on this motor? i.e. only pull one spark plug at a time? or pull all then check each cylinder?

Thank you,

Jon
 
Here is my findings.

Cylinder # 1 = 90 psi
Cylinder # 2 = 90 psi
Cylinder # 3 = 90 psi
Cylinder # 4 = 90 psi

There is absolutely no difference in the readings, not even a fraction.

And this was with all plugs removed, and using a brand new compression gauge with screw in fitting, and cranking the motor over many revolutions and the same for every cylinder.
 
I also checked the spark on all 4 plugs and it is strong, blue, and hot Comp.jpg
 
Throttle should be wide open when checking compression. Numbers should be around 125psi, but they are even so maybe high hour engine? Did you release the gauge back to zero before checking the next cylinder. Seems odd they are all the same. As a caveat many engines run good with compression that low.
 
Last edited:
Yes I did (of course) release the pressure on the gauge before proceeding to the next cylinder. And the butterfly valves in the ventura opening in the carb's were in the closed position.

So where do I go from here?
 
It's possible I found the issue. Every time I rebuilt or cleaned the carburetors, I never did remove the "intermediate calibration pocket core plugs"

Is there a jet, or orifice under them that could be plugged? I know when I first got this motor the idle jets behind the float drain plugs were for sure plugged and I had to take a small wire to clear them, and afterwards clean them good with "gumout"
 
Yes I am using "Champion" QL77JC4. and they are brand new gaped to .040 Yes the motor is up to temp. Yes all four plugs were fouling equally, they were very wet when removed after it dies.

I have the carbs off now, and did order new "viton" needle & seats, thinking the steel ones that came with the kit I installed last week were not as good as a "viton needle"

Also when I put in the new needles & seats, is it safe to run in a test tank of water without the prop on at high and low RPM? Every time I do something for a fix to this issue, I have to drive to the lake a mile round trip only to find out it dies after running and idling it back down.

And by the way this is a 110 HP Johnson.
 
badcrank 777 said:
Yes I am using "Champion" QL77JC4. and they are brand new gaped to .040 Yes the motor is up to temp. Yes all four plugs were fouling equally, they were very wet when removed after it dies.

I have the carbs off now, and did order new "viton" needle & seats, thinking the steel ones that came with the kit I installed last week were not as good as a "viton needle"

Also when I put in the new needles & seats, is it safe to run in a test tank of water without the prop on at high and low RPM? Every time I do something for a fix to this issue, I have to drive to the lake a mile round trip only to find out it dies after running and idling it back down.

And by the way this is a 110 HP Johnson.
Click to expand...
NO,not a safe or good thing to do .you wont be able to duplicate.
Would it be more convenient to take it to a repair shop?
Post your results.
Who's/what service manual are you using?
What are you calling a test tank? Mine holds 650 gallons and we use test props.
 
Thank you for alerting me. I will put the prop back on.

I would take it to a repair shop but we have none here, and the ones within 100 miles don't work on Johnson outboards.

I am using the original OMC "Johnson Evinrude" "CU" Cross V service manual P/N 507618 covering 88 thru 110 / 150 thru 175 models.

Test tank is a 50 gal drum.

Is there anything that could be an issue under the "intermediate pocket core plugs" ? I have never taking them out and will not unless I have to. I do have new ones.
 
I have not installed the new "needles & seats" they should be here today or tomorrow.

The primer valve is working properly and I do have the "red" lever inline with the body of the solenoid.

I removed one of the core plugs on the carb, and everything was super clean, so I installed a new one, and checked the rest of those ports that lead to the two small holes that lead into the ventura and they are super clean and "gumout" flows freely through all of them. Prior to all of this, I disassembled both carb's and removed every jet , thoroughly cleaned everything, made sure all jet orifices were super clean etc, install all new gaskets.

I am going to fill the test 50 gal bucket with water, install the ear muffs on the water intake with garden hose attached, cover the bucket to contain the water so I can put it in gear and go to a higher RPM then back to idle to see if it will die, after installing the new N & S's. I also did re-install the prop.

Everyone I talk too keeps referring me back to float level, so after I install the new "viton" N & S's I will set the float level 1/8 in higher then spec. so the gas flow will shut off sooner. And if it still dies after running High RPM and then returning to idle, I am going to be at a total loss as to what to do.
 
Yes I sure did, along with every other jet that I had removed, and they are all sparkling clean. I also done the idle tube leakage test to make sure there was no leakage between the idle tube and the carburetor body.
 
Some will argue.----Compression values of 90 PSI are a concern.----A new head gasket is cheap.---Take a cylinder head off and have a look in there.-----You can clean carburetors all day long but 90 PSI indicates a problem to me !
 
Ok, But I know 90 PSI is low, but this is a old motor. And with that low of a reading, why does it run so good and smooth at WOT with tons of power, also why does it idle with no issue. It is only when I slow it down from WOT to below 1000 RPM does it start to sputter and die, and floods out?
 
SUCCESS!! I want to thank everyone who gave input to the forum. I finally have a 1987 Johnson 110 HP V4 VRO running perfectly!!

What happen is that I installed the new needle & seats, raised the float level 1/8 in above spec. Which was the real cause of the issue, I will never know.

But to have this motor performing, and the boat in beautiful shape, makes for a happy camper. Now I can enjoy the summer on the lake.

Thanks to all,

Badcrank
 
Interestingly enough, when I installed the first carburetor kits I ordered OMC "original" Johnson oem kits. which came with needle & seats. The second go around I ordered just the needle & seats from a different Co. And they also were OEM Johnson. But I could see that the "viton" needles were of better quality.

Like I said, whether it was the needles or me raising the float level 1/8 " above spec I will never know.

Also to whom it may concern, in that year they made a "high" compression engine and a "low" compression engine. Mine at 90 PSI I will assume was the low Boat 2.jpgcompression engine. At any rate it runs perfectly and very strong, and at 4500 RPM it screams and powers my 16' Monte Carlo like a rocket ship.
 
Low compression head gaskets were offered for many years.------In my local a 1987 crossflow with 90 PSI on my gauge would be coming apart.---Perhaps a dealer installed the low compression head gaskets when new.---Also depends on quality of gasoline available.-----Your location ?
 
Yes and I have no way of knowing the history of this 1987 V4, because I purchased this boat & motor from a guy that it had set in storage for 3 years. It took me a long time to refurbish the boat, and as you know the motor was giving me fit's for quite some time, but all is well now.

I am in Cheyenne, Wyoming. And I only use non alcohol fuel mid grade, of which we can purchase here in Cheyenne. A little pricey but worth it in the long run.

I also add a little "sea-foam" It is a fabulous product, and I swear by it, use it in all my vehicles.
 
Back
Top