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Setting proper idle on 87 Johnson 88 SPL.

G

GLE3

Member
Hi, I have a new to me 87 Johnson and recently rebuilt carbs and replaced water pump. I mounted it on my boat and reconnected the throttle and shift cables. After I finished all that I fired it up and it had a very high idle. Even for starting it in the yard with a flush. Not sure if it was the cable I mounted or the carb rebuild but i guess maybe I didn't put things back the exact way they were took off? I noticed that the cam roller isn't lined up properly with the notch on the throttle arm. Do I need to make adjustments to the carb linkage etc.. or the throttle cable? Thanks for any help!
 
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First, inspect the throttle roller to make sure that the outer cover of it hasn't broken away (if it's a two piece roller). It should be approximately 3/8" in diameter... if not, the outer clear cover has cracked and broken away, causing the diameter to drop to approximately 1/8"... in which case, replace it.

Now, back off the throttle roller. loosen the retaining screw and back it away from the cam so that there is no tension applied to the carburetor linkage.... then adjust the throttle butterfly linkages between the carburetors so that the butterflies open and close at the same time.... You do not want one set of butterflies closed and one ever so slightly open.

What's left is to adjust the throttle roller so that the throttle butterflies just start to open when the scribe mark of the cam is dead center with the roller... not before or after. Secure the roller with the set screw

NOTE: The adjustable linkage between the vertical throttle arm and the cam... DO NOT tinker or attempt to adjust that rod as that controls the "idle timing". If someone changes the length of that rod, it will be necessary to check and re-set the idle timing as per ones service manual. This must be accurate in order for the above settings to be accurate.

Now, with the linkages set properly, adjust the throttle cable at the adjustable threaded trunion that's clamped to the engine. Find the idle stop screw that's somewhere in that vertical throttle arm and back it away from its stop. loosen the bolts that are clamping the throttle trunion to a point where you can turn it. With the engine running, turn the trunion and get the idle to where it belongs. Race the throttle slightly a couple times to see where the idle drops to and adjust as needed.

On a flushette, set a 20" shaft model to 1000 rpm... a 25" shaft to 1200 rpm.

When you get the idle where it should be (as above), screw the idle stop screw in just to where it touches so as to keep the idle from dropping lower due to vibration etc.

Tighten the bolts retaining the throttle cable clamp. That's it.
 
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Thanks Joe! I synced the carbs and set the roller on the scribe. What I am left with is a cable that is too long to fit back in the throttle plate. Do I have the cables backwards? Or is there an adjustment I'm not seeing? Is this where I should be adjusting the idle screw at the top of the throttle? Even if I back the trunion all the way till there is no thread showing nearest the throttle arm it still is too long . Trying to cut down picture size so I can post something..
 
Picture IMG_20190722_142802.jpg

IMG_20190722_144055.jpg
 
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Thanks racer verified that's the throttle cable so it's connected the right way... Adjusting the throttle cable only involves turning the circular plastic part right? Not sure what else to adjust or if the idle was right before I got it
 
GLE3 said:
Thanks racer verified that's the throttle cable so it's connected the right way... Adjusting the throttle cable only involves turning the circular plastic part right? Not sure what else to adjust or if the idle was right before I got it
Click to expand...

There is nothing left to adjust which indicates that something is not as it should be.

If that loose cable is indeed the throttle cable... I would think that something is not as it should be on the other end.
 
Thanks again for your help guys... Anyway, I swapped the cables just to see what's what and the throttle works ok now but I don't have forward gear. Reverse and neutral but no forward. Figured I could just adjust the trunion but it gets worse instead of better. With the cable disconnected it seems I have the distinct positions on the shifter. Any other ideas? I can water test if I would need to.
 
I get it racer, but I am close now. I can only get forward if I push on the shift lever. Doesn't matter if cable is connected or not. Tech at local Marina says the lower unit is going if this happens? Truth to this? I'm 99 percent sure it's mounted right now..
 
GLE3 said:
I get it racer, but I am close now. I can only get forward if I push on the shift lever. Doesn't matter if cable is connected or not. Tech at local Marina says the lower unit is going if this happens? Truth to this? I'm 99 percent sure it's mounted right now..
Click to expand...
Did you have the prop turning while you were trying to shift? Turn the prop while you are shifting do not have the motor running when you are doing this.
 
Has the lower unit been off recently, and if so... did anyone turn that shift rod? That would affect the critical rod measurement which would make it impossible to adjust the shift properly.
 
Was shifting while at the dock when testing everything was done under power. Shifted controls to forward then pushed lever forward a 3/8 inch and she shifts.

Tried turning the prop with engine off.

In forward gear - prop turned reluctantly clockwise. Harder to turn the other way made it 4th turn and stopped but could have possibly turned more but didn't want to horse it

Reverse was opposite..
 
joereeves said:
Has the lower unit been off recently, and if so... did anyone turn that shift rod? That would affect the critical rod measurement which would make it impossible to adjust the shift properly.
Click to expand...

Tech at the Marina asked the same thing. I did a water pump and may have turned the shift rod once only to center the hole so I could fit the tooth in. Also moved it with a screwdriver when I was trying to set it in the tooth
 
Hey, just a final bit on this story in case someone can benefit... Shift rod was five turns high out of alignment. Guess they make a special tool to check height but I 'built' my own using a wooden yardstick, a drill that drills a straight hole, a #10 3 inch bolt and a nut/washer. Manual had specs on the proper height of the shift rod so you just have to drill the hole at that height, assemble the bolt/nut/washer, and measure the lower unit from the top of the gearcase and bolt should be at the same height as the small hole in the shift rod. If not, turn to adjust.

While I admit to possibly a couple turns while installing the lower unit originally, the spot where the trunion was before I started messing with it suggests it was probably 3 turns out of alignment to start with.. Thanks Joe for your last comment there!
 
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