88 hp Johnson V-4, carbs don't open all the way at full throttle

LuvMyBrownDog

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I recently bought a boat that has a 1988 Johnson 88hp V-4 on it. The guy that sold it to me told me that "some kids" screwed with the idle and so the idle knob needed adjusting. I don't think anyone screwed with the boat, but here's the problem. Pushing the stick/throttle all the way forward does not open the carb throats all of the way. I have checked this visually, and confirmed that is what is going on. The engine idles slowly and beautifully, shifts into gear smoothly, but doesn't open up all of the way at full throttle. I don't know how to adjust the carbs to allow them to open all the way at full throttle. I'm hoping this is a simple adjustment, please help. [I can post pictures somewhere if that will help diagnose the problem]
 

BonairII

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

There should be a set screw(s) that you can loosen.....then close the butterflies...then re-tighten screws.

Your motor may need to have the "link-n-sync" done on it...to make sure carbs are "in sync" with spark advance.
 

boobie

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

Sounds like you need an OEM Factory Service Manual. All the correct procedures are in there.
 

LuvMyBrownDog

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

Sounds like you need an OEM Factory Service Manual. All the correct procedures are in there.

That sounds like a good idea. One of my buddies told me that it is possible that Johnson designed the motor so that the carbs wouldn't open all the way. Kind of like a restrictor plate, to limit the motor to 88hp. Does anyone have any experience with an engine design like this?
 

boobie

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

Your buddy is wrong. The throttle plates have to be flat at wot as like all mtrs. If they go over center it can actually cut down on your rpm.
 

emdsapmgr

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

That 88 is actually a true 90, but an economy model without some options, like no VRO, power trim was an option. It may be a simple as an adjustment to the throttle cable just inside the lower engine cover. Or you may need to do a "sync and link" as boobie mentioned. Agree: When you get into this process, best to have the correct factory manual.
 

LuvMyBrownDog

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

Or you may need to do a "sync and link" as boobie mentioned.

You guys are being very helpful, and I appreciate it immensely. At the risk of sounding ignorant, and I am, what is a "sync and link"?
 

BonairII

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

No. Seloc and Clymer etc are aftermarket manuals.
 

emdsapmgr

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

If the adjustment of the throttle cable is spot on, you'll have to do the sync and link. This process is very specific and exactly syncs the throttle plate openings with an exact amount of spark advance. You need a manual to get this right.
 

boobie

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

Stay away from Seloc and Clymer as they Suck !! Best thing to get is the OEM Factory Service Manual.
 

LuvMyBrownDog

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

My throttle plates don't come anywhere near flat at wot, that is my problem. Push the stick forward, the throttle plates open less than have way. How do get the carbs to open all the way without increasing the idle? Could a stretched throttle cable be causing this?
 

emdsapmgr

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

You need to double check the throttle cable adjustment just inside the lower cowling. Unbolt the throttle cable inside the cowling. Move the spark advance lever on the side of the engine by hand, through it's idle to WOT range. Make sure you don't overrotate the lever so that the carb butterflys begin to slightly close. Have another person move the throttle handle at the same time. Observe the range of movement of the cable end with that you get by hand with the bolt on the spark advance lever. Likely the hand movement range does not match the cable end movment range and requires adjustment.
 

JDusza

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

Very likely your throttle cable will be out of adjustment as emdsapmgr suggests. If idling fine and not open full throttle, for the same amount of cable, if you readjust to open full throttle, you'll not be able to close to idle.
Check the cable.
J
 

roncummins

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Re: 88 hp Johnson V-4, carbs don't open all the way at full throttle

I recently bought a boat that has a 1988 Johnson 88hp V-4 on it. The guy that sold it to me told me that "some kids" screwed with the idle and so the idle knob needed adjusting. I don't think anyone screwed with the boat, but here's the problem. Pushing the stick/throttle all the way forward does not open the carb throats all of the way. I have checked this visually, and confirmed that is what is going on. The engine idles slowly and beautifully, shifts into gear smoothly, but doesn't open up all of the way at full throttle. I don't know how to adjust the carbs to allow them to open all the way at full throttle. I'm hoping this is a simple adjustment, please help. [I can post pictures somewhere if that will help diagnose the problem]

It is simply missing a roller that goes on the throttle postion
 
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