1979 johnson 85hp v4

[jimcrain1966]

1979 Johnson 85hp v4 cranks too slow. battery is fully charged and engages flywheel, but seems like not enough power, takes 20 seconds to revolve once.

 

[emdsapmgr]

Re: 1979 johnson 85hp v4

Dirty, corroded wire terminals are a good place to start when looking at starter issues. If they are clean, you can test the starter: use a set of automotive jumper cables direct to the starter-with a known strong battery. If the starter cranks normally with this test, it's ok. At that point, you may need to replace the starter solenoid. With age, the solenoid contacts can get burned and not transfer enough current to properly spin the starter.

 

[boobie]

Re: 1979 johnson 85hp v4

Take the battery to a parts house and have it load tested.

 

[jimcrain1966]

Re: 1979 johnson 85hp v4

cleaned all terminals and wires, still does same thing. when testing starter with cables, do I take starter off or leave on? I also took a 15 second video to show whats its doing. any way for me to send to you?

 

[jimcrain1966]

Re: 1979 johnson 85hp v4

Take the battery to a parts house and have it load tested.

bought new battery, does same thing

 

[V153]

Re: 1979 johnson 85hp v4

Replace starter

 

[boobie]

Re: 1979 johnson 85hp v4

Well, maybe it's time to take the starter to a rebuild shop and have it checked out.

 

[Bob_VT]

Re: 1979 johnson 85hp v4

Even if your wires look good....they could also be corroded on the inside of the plastic casing. I had a similar problem years ago and had new main wires made at a local battery shop.

I would absolutely test the starter first

 

[emdsapmgr]

Re: 1979 johnson 85hp v4

Leave the starter on when you test it. You need to know if it will spin the flywheel normal rpm's when jumping it.

 

[James R]

Re: 1979 johnson 85hp v4

In my experience it is the starter motor on a engine this old. Also automotive jumper cables dont make a good enough connection to pass the needed current. The only way is to wire the starter motor directly with good battery cables to be sure of a valid test.

 

[jimcrain1966]

Re: 1979 johnson 85hp v4

Well, maybe it's time to take the starter to a rebuild shop and have it checked out.

bought new starter and solenoid. still does same thing. wondering if not enough fuel oil mix left in cylinders to make easy rotation.

 

[Crosbyman]

Re: 1979 johnson 85hp v4

2 cents..

jumping is still order especially since you have a new starter and selenoid...cost nothing to try direct 12V. Make darn certain starter is properly grounded. see how it reacts with direct feed from the battery. If it looks like it is torquing with more speed and force... time to recheck connections...

time to back up and work backwards to the battery. (assuming nothing machanically wrong with the engine)

btw can you measure voltage across the starter while cranking... to low a voltage may indicate coroded cables or simply corroded crimps ??.

 

[Bosunsmate]

Re: 1979 johnson 85hp v4

bought new starter and solenoid. still does same thing. wondering if not enough fuel oil mix left in cylinders to make easy rotation.

Pull out the spark plugs and try turning flywheel clockwise by hand. It should be pretty easy to do, check that there is no binding anywhere.
Spray some two stoke mix or oil into the cylinders while you a at it.

 

[jimcrain1966]

Re: 1979 johnson 85hp v4

connected battery directly to starter with new cables, still does same thing. can I spray wd40 into cylinders to see if bound up?

 

[jimcrain1966]

Re: 1979 johnson 85hp v4

New batt has 675 cranking amps,is that enough?

 

[V153]

Re: 1979 johnson 85hp v4

When was the last time this motor ran. Have you done a compression test?

edit. Have you tried turning it over by hand?

 

[F_R]

Re: 1979 johnson 85hp v4

Ever hear of voltage drop tests? Do you know how to do them? That should have been the first step before replacing stuff.

 

[James R]

Re: 1979 johnson 85hp v4

I use a mix of two stroke oil and Marvel Mystery Oil and shoot it into the plug holes. Frees things up pretty good however I shoot the same in into the carb throats with the throttles open. This gets sucked into the crankcase when the motor is turned over. Most of this gets shot out of the plug holes and the remainder gets burned off when the motor fires. You can use a socket wrench on the flywheel nut to rotate the motor. If the motor locks up don't force it. Let the oils work.

 

[emdsapmgr]

Re: 1979 johnson 85hp v4

It's worth your time to take the starter apart. Check the comm on the armature. If it looks good (probably) reuse it. Possible the brushes are bad. You can purchase a replacement set for the motor. Also likely the starter is full of carbon black, so a good cleaning will be inorder. Plus, re-lube the bushings with some 2-4-c white lithium grease. This is not a difficult thing and could save you some $

 

[boobie]

Re: 1979 johnson 85hp v4

I believe the OP said he bought a new starter in post # 11. But a good question would be, is it new or a used one ??