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2000 Johnson 150 comp test fail

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bp_redbear

New member
Howdy.
I have purchased a fine little ol' 1979 Hammond v1900 El Dorado (19' outboard) in very good condition with a trailer, pushed by a Johnson 150 Fast Strike (2000 J150PXSSC) 60° carbed V6.

I have both a SELOC 1311 and a OMC/Johnson "2000 SS" service manual.

Short version:
Unable to perform a compression check, as the motor won't crank in WOT. I cannot find the "WOT" button, anywhere! Kidding!

I am getting only 60-65 psi on each cyl, but that's with the control in Neutral. It won't crank in WOT. Am I correct that something is preventing the motor from spinning properly for the test because it's in neutral and not full throttle? It's got an Evinrude white control box (no lanyard kill SW).

I ran the motor up to operating temp, (on muffs with water on, idle-to-high-idle speed), then stopped the motor.
The spark plugs were then removed, inspected, & notated what cyl each went in.
A compression tester was attached to a cylinder.
I am unable to get the motor to crank @WOT. The motor will turn over in neutral, but when the control lever is moved to Forward, Full Throttle, the motor won't crank.
I suspect that the motor is intended to be started only when in Neutral, but both manuals simply state "run motor to oper.temp,,, stop motor,,, remove plugs,,, attach tester,,, run motor same amount of revolutions for each cyl, at least 4 revolutions in full throttle". I can jump the starter to get the motor to spin with the control in full throttle, but still am only getting 60-65 psi. Something is telling the motor "I'm not in Neutral, don't spin full speed". Am I correct? What am I doing wrong? I pray that 65 is not the best compression. I'm looking for ~110-120, if I am not mistaken.

After the failure that I had with a 16' 4Winns and an '87 Rude 3 cyl. 70hp (blown head gasket, damaged #2 cyl - no compression), I started with the compression test first, instead of last.

This V6 150 seems to run very good, has a working VRO pump, new battery, and from what the previous owner told me; never run hard. New water pump a couple of years ago (he said he paid a mechanic $600 to rebuild the lower. I asked if he meant the gearing mechanism or just the water pump. He didn't know, at least the pump).

His wife got it from her grandpa who bought the boat and trailer new in '79. Not sure how it came to have the 2000 150 FS, but that's all I was told. It's a sharp boat, and I am trying to get a benchmark reading of the motor.

Anyway, I suspect that this motor has been gently used. The gent said about 4000 rpm is about as high as he'd revv it.
 
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faztbullet said:
Try a different tester and your looking for 90+psi as that motor has compression relief ports
Click to expand...

See if you can borrow or get a loaner compression tester and recheck the readings.
60-65 on all 6 cyl. of a good running engine leads me to think your tester may not be accurate.
 
I went through 3 brand new Amazon testers, they were all crap. Broke down & bought a quality unit from a reputable tool manufacture. Test the one you have on your lawn mower, if shows low readings, & your mower is good…the gauge is garbage.
 
New readings:
MAC Tools CT-25 0-300psi Comp. Tester gives readings of:

Port (Top-to-Btm) 96, 98, 100
Stbd (Top-to-Btm) 95, 99, 101

Motor @ oper. temp.
Gears in N
 
It is O-K !
And, that makes me happy. I believe that I was not given full information from the previous owner. The motor may "run good", but I am leaning towards the prospect that maintenance items have not been done. The anode was severely corroded, doing it's job, but probably past due. I see corrosion in a couple of places.

I've had an instance of the "NO OIL" light coming on. Even if I squeeze the bulb on the VRO tank hose, prior to starting.
I've also had a water temp alarm and watched the temp gage indicator rise, confirming that. In both instances I shut down the motor, immediately.

So, I've installed a new water pump, new gear oil, new anode, new fuel filter on the motor, new thermostats & springs, new spark plugs.

The overboard indicator has a much stronger stream, now. Although the water temp gage doesn't seem to move off the pin. (I was running the motor in a bucket, w/hose). It's not rising above 100, even though I am sure the motor reached 140 and opened the t'stats.
Some things that the previous owner told me don't seem to square up with my experience with this motor (and boat), so far. Unless the guy was just clueless.

He said that the oil pump worked well. Never had to mix oil in the fuel, simply adding gasoline to the fuel tank and oil in the VRO oil reservoir.

On a brief trip out on the water the NO OIL
light lit up on the System Check gage, at startup, while warming the engine. I had even squeezed the primer bulb. It was firm.

So, to eliminate the NO OIL condition I grabbed the 6 gallon OMC fuel tank and mixed 50:1. I'll use that in the mean time. I believe that the vro pump is not self priming, as it should. Even though the bulb has been squeezed every time the motor has been run. I'd like to use the VRO, as opposed to mixing oil in the fuel every fill-up, but I believe that I lost confidence in it, until I can test it thoroughly.

But, seeing the compression readings @ 95-100psi is a good starting point!

I believe that the idle is a bit high. I'd like to Link & Sync.
 
For your oil, mark the oil level on the reservoir very carefully with a pen and monitor the consumption. It won’t tell you if the correct amount of oil is being mixed but it will tell you that the oil level is dropping (or not) Keep using the premixed gas tank in the meantime
 
I've got marks on the oil tank. That NO OIL light is a deal breaker. Until I troubleshoot it and test all the functions I'll mix manulally.
But, even still, that's a 23 yr. aged VROom system and if anything it seems like it's been using more oil than less. I love the idea. But, I finally got me a good motor, I don't want to eff it up.
 
bp_redbear said:
I've got marks on the oil tank. That NO OIL light is a deal breaker. Until I troubleshoot it and test all the functions I'll mix manulally.
But, even still, that's a 23 yr. aged VROom system and if anything it seems like it's been using more oil than less. I love the idea. But, I finally got me a good motor, I don't want to eff it up.
Click to expand...
These OMS (Oil Monitoring System) pumps are designed to over oil when they fail. If you are getting a lot of smoke and excess oil consumption, then you likely have an OMS pump with a bad fuel side. The NO OIL warning could be a failing sensor on the oil side of the pump.

These are plastic/rubber parts that don't last forever, so it's possible a 23 year old vacuum/piston driven pump is ready for replacement. You can also hook up a measured bottle of 2-stroke oil to the pump, then run the engine until you burn through a gallon of fuel. You should burn about 2..5 ounces of oil for every gallon of fuel. If the usage is significantly more or less then you have a pump problem.

KJ
 
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