Evinrude/johnson V4

Michaeljur

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Jan 17, 2009
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I have a V4 motor , elctric gearbox 1970 model , it starts and runs in neutral fine revs up fine then all of a sudden the prop starts turning and the motor revs up high , I push the forward buttons etc but makes no difference I cannot rev the engine. I switch key off the motor stops , the next day it starts fine and the same thing happens after a while it switches inot to gear on its own and revs high. HELP HELP HELP , cheers michael
 

tashasdaddy

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51,019
Re: Evinrude/johnson V4

sounds like so timing or throttle linkage is sticking. and you may have a switch going bad, or short in wiring. are you using Premium Blend type C lower unit fluid?
 

Michaeljur

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Jan 17, 2009
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Re: Evinrude/johnson V4

it has good fluid had it seviced impellor etc . It runs fine at first timing is ok , I have been told it might be the shift diode , or rectifier this motor is old it has the amplifier system , but comps are all 125 so I want to keep it but no one here wants to look at it, it just suddenly jumps into gear yet the swithes on control box is still in nuetral, when jumps into gear the whole motor runs rough. Yet when I first start it and put into gear all goes well for about 5 minutes.
 

tashasdaddy

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Re: Evinrude/johnson V4

you are correct, most mechs do not want to touch them, they don't understand them, and parts are extremely hard to find, and then expensive. if you plan to keep it, order yourself a service manual and make it your best friend. outboardbooks.com
 

F_R

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Re: Evinrude/johnson V4

The first thing to consider when diagnosing one of those motors is that it is designed to be "fail-safe". That means that if anything goes wrong with the shift, it automatically goes into forward gear. Sounds to me like that is what is happening. So.o.o.o.o, the task is to find out what is going wrong. It could be hydraulic (in the lower unit) or electrical (anywhere else in the boat).

My money is that it is a 98% chance it's electrical. Especially since the engine runs rough when it happens. If it were not for that rough running part, I'd seriously suspect the shift switch is bad--a common problem. But the rough running introduces a bunch of other stuff all the way from the battery to the ignition switch to the control, and back to the motor.

Your best friend for locating the problem is a wiring diagram (comes with the factory service manual) and an understanding of how the system works, and a volt-ohm meter and a knowledge of how to use it.

We at the forum can guess all day and might hit upon it. So can anybody else not actually in the boat with the above resources.
 

Dhadley

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Feb 4, 2001
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Re: Evinrude/johnson V4

OK, we're going to look at something kinda odd but just keep an open mind.

When it starts and is running OK in neutral then jumps into gear & revs up, is the flywheel and prop both turning clockwise? Or counterclockwise?
 

Michaeljur

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Jan 17, 2009
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Re: Evinrude/johnson V4

Hi , yes it turns clockwise when 1st started then it turns anticlockwise and runs rough , also the flywheel has sheered off the keyway key
 

Dhadley

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Re: Evinrude/johnson V4

Good info. When you pull the flywheel to replace the key look closely at the anti-reverse spring. If it's worn or non-existant you'll need to replace it. Then look at your battery. There are very specific battery requirements for that motor. Also look at your distributor cap & rotor. Over time they can develop carbon trails which can lead to misfiring or in extreme cases let the motor run backwards.
 

tashasdaddy

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Re: Evinrude/johnson V4

it starts running correctly, they for some reason, it is runs backwards. seem there is a plate that has failed allowing it to run backwards. it is involved with the shear woodruff key and fly wheel.

F_R, and Dhadley can give you the technical terms.
 

Michaeljur

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Jan 17, 2009
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Re: Evinrude/johnson V4

Thanks heaps guys , so why does it jump into gear without pressing forward button. is it the switch in the gearbox or the switch at the control , cheers michael
 

Dhadley

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16,978
Re: Evinrude/johnson V4

It has to do with the oil pump in the lower unit. That motor shifts on oil pressure and is pre-loaded to forward. If you lose pressure it'll be in forward. IE - when the motor is not running it'll be in forward. When the motor runs backwards it's turning the pump backwards.
 

Michaeljur

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Re: Evinrude/johnson V4

cheers and thanks for all your tips , I fixed reverse spring under flywheel , I changed gearbox oil . All was ok at home in test tank , when I put boat in water just going slow the motor just cut out . No spark on any cylinder so I did all tests according to an old manual it seems the pulse pack has failed, I cannot get one under $560 au . it seems a lot for this age motor. But I dont wont to just throw this motor away it has even 120psi on each cylinder, cheers michael
 

Michaeljur

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Jan 17, 2009
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Re: Evinrude/johnson V4

I should mention it is a 1969 85hp evin v4 , I have been told that I should put on a gt40 coil that is no restistance with a condensor off a corolla KE 20 point distributer , instead of the pulse pack , what do you think . cheers
 
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