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1988 Johnson VRO 140hp looper timing

N

nwredsox

New member
Hello everyone. I keep trying to post this but I don't see it on the forum. I have been reading this forum since I bought my boat a few years ago and it has been really helpful. Ive never posted before but I'm a little stuck and could use some advice.

My engine runs and I have done all recommended maintenance that I have seen on the site last 3 years. I have factory service manual and follow its specs. End of last year motor started running a little more rough than it had. Cutting out at idle and the sound of the motor at middle to WOT seems to change its sound/tone at times while running. No discernable change in power. This year I'm noticing gas/oil slick in the water behind the boat that Ive never noticed before. No gas leaks anywhere that I can find. Lower unit oil is perfect.. I have...

Rebuilt the carbs with new BRP kits.
New fuel filter
New Champion plugs
ran diagnostic on VRO as per manual all OK
Checked spark and got consistent 7/16 gap spark x4
Compression test #1 121 #2 123 #3 131 #4 122 (this was a change from last year as all were within 3 psi. It is still within 10 but it is a change. I do run OMC engine tuner 1x a year)

The only thing left is the timing. I'm taking the boat out tomorrow to finish the sync and link. I was testing the timing light and I can see the engine jump every other second or two about 3 degrees on the flywheel that coincides with the rough running. I'm not sure if that is normal or not.Checked the timing. Maximum spark advance was 1 degree off. Yes I sat in the back of the boat with it going 4700 rpm. No adjustment made. Then I got to the idle timing and it was way off. Supposed to be 8 atdc it was 4 btdc. kept turning the idle timing screw in as per the manual. the motor increased rpm until the screw bottomed out. timing went to tdc and would go no further. It was reving over 1000 so I backed it out to the original local and called it a night as I didn't want to bust up my lower unit. Still have an oil/gas trail in the water. Is my problem likely under the flywheel? Ill have to study up on the manual I don't know about the key (I have not checked it but I don't have the tools to pull the flywheel yet.. I hope its not rebuild time. I don't think I know enough to do it myself manual or not.

Maybe I shouldn't worry about it and just thank my lucky stars that it runs. I'm trying to make this engine last as long as I can cause I cant afford a new one so I'm always nervous that the thing is going to blow b/c I didn't do something. Its never been rebuilt and I have no idea how many hours are on it. No mechanic in my area wants to touch it. One mechanic quoted me 1000 dollars to rebuild the carbs just to get me off the phone and they all say..well its old what do you want? Any advice?
 
Check out my saga on my 1986 225hp and you will get an idea of what it takes to restore these old engines, but the rewards are great. I did everything myself using the manual and the advice of many of this forums experienced members. I did have to buy some of the testing equipment for the ignition and tools to remove the flywheel, but I fixed all that I found wrong and I'm enjoying a powerful engine on my 23 footer. As per your last paragraph, you can rebuild the carbs yourself (I did all 6 of mine in one afternoon!) and it fixed many of my problems. I would be careful with the WOT timing and get it set right. Look up the easy procedure at the top of this forum to get started. Set the idle in the water and you'll be all set.
 
I have a factory service manual and followed those steps for timing. Not that there is anything wrong with Joe Reeves method. I just thought the manual way would leave less room for error. My trouble is that I cant adjust the idle timing where it is supposed to be. Even with the idle timing screw all the way in the motor will not go ATDC which I think is 4 degrees ATDC is what the manual calls for. Right now it fires BTDC. Maximum spark advance at WOT is where it is supposed to be. any ideas?
 
First of all you only " set " maximum timing advance.--------Believe it or not idle timing looks after itself !------Idle timing value in your manual is where the throttle plates open up and thus it is a linkage / carburetor adjustment !
 
Hmm.. My manual has me using a timing light to adjust the idle. One screw on the left is for adjusting timing at full throttle. The other on the right is for idle timing when the boat is in forward idle with throttle plates closed. My carbs are non adjustable unless you change out jets. The idle set for rpm is on the throttle linkage. I have heard that the idle timing takes care of itself before. Maybe I will just leave it alone.
 
Throttle plates are " closed " but they are not really closed !!------They must allow a metered amount of fuel with the all important oil into the engine for lubrication.-----Thus the speed of the engine is controlled by retarding the timing.-------An engine in good condition can be retarded more than a so,so engine.---------The idle timing value in the book is where the throttle plates start to open.
 
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