1989 Johnson 90hp Slow Crank

[cr295]

Recently I have been having an intermittent slow crank situation while out on the water. It seems to occur after I have been running for a while and after the motor is off for anywhere between 15 minutes to 2 hours. Upon attempting to restart, it cranks too slow to re-start. The starter is always engaging the flywheel but doesn't seem to have enough rpm to get it running. The condition never replicates itself while at the dock or while starting on the hose.

Fortunately I carry a booster box with me and the three times out of thirty or forty successful starts I had the problem, I have only been able to get the engine going by connecting the positive jumper to the top post of the solenoid (battery side) and the negative to the negative bolt on the starter. I then go to the key switch and it cranks fast like it should and I immediately get restarted. The few times this has happened, it would never restart connecting the booster box to the battery itself. I load tested the fully charged 1 yr old battery which was fine. Even though all the applicable wires terminals looked fine, I disconnected them and wire brushed both sides of each connection and the adjoining posts.

Frustrated at this intermittent problem I even took the battery cable completely out and cut back a several inches looking for corrosion near each end- I found none. I closely checked the entire length of the cable for nicks or insulation problems. None were found. I securely re-crimped the lugs with a hydraulic crimper and used HD heat shrink on each connection. After doing this most recent inspection and repair I thought I had the problem licked but after running flawlessly for five days and dozens of successful starts, on my last outing, it occurred again.

My multi-meter was not functioning at the time nor did I have anyone to assist me, so I could not get a voltage reading at the solenoid or starter connection while cranking. My deductive reasoning (fallible as it often is) leads me to believe that I have a bad battery cable and the solenoid and or starter is not getting enough voltage. I would have liked to test it properly at the time but I could not. The boat is several hours away in a remote location and there is no local marine parts suppliers nearby so I have to import (bring with me) what I need to fix any given boat projects.

Would the conditions I described warrant just ordering the custom made cable? I'd hate to spend the money on the wrong thing but there again if I want to use the boat when I go back I have to have what I need with me. Could there be a condition with the starter or the solenoid that could cause this? I'm thinking not because when 12 volts from a known good source was applied it would always crank properly. I would appreciate any input from those with diagnostic experience of this nature. Thank you in advance for any assistance you can render and for your time and patience reading through all this.

 

[emdsapmgr]

You said the starter would crank normally when the battery pack was used. Normally, I'd suggest that the internal contacts inside the starter solenoid are burned. But the way you hook up the battery pack to the starter, the pack voltage still goes thru the internal solenoid contacts. I'd suggest another test. When the engine won't crank, connect the battery pack direct to the starter and see if it cranks normal rpm's every time (bypass the solenoid.) You may decide to replace the solenoid at some point. (not an expensive item) It is also possible that one of the main battery cables is damaged internally preventing full current transfer. Not uncommon with older engine battery cables. As a last option, you may want to pull the starter apart. Visually check starter armature commutator for pits, burned areas. If it's still smooth and shiny, the starter brushes may show signs of wear and may need replacing. I'd clean out the carbon inside the starter and re-lube the armature bushings with some white lithium grease prior to reassembly.

 

[racerone]

Those starters are easy to inspect / clean , easier than you would think.-------They are damaged all the time by too much continuous cranking.

 

[cr295]

Thanks for the replies and wisdom. I have a new set of cables coming as well as the solenoid.

BTW, I have a identical, spare (blown) motor that I got for cheap. At one point I tried swapping the starter from it but although it spun plenty good the drive gear would not push out far enough to engage the flywheel. On these starters it looks like centrifugal force pushes the starter gear up to the flywheel? Although I have a reasonable amount of mechanical aptitude, I haven't ever torn into starters before. This spare may be the one for me to take apart and experiment with. Is there something other than a good degreasing and "relube" that will allow the drive gear to push out far enough to engage? Where would one order the brushes or other internal components from for this starter?

Thank you.

 

[Watermann]

I don't know how a battery cable being bad would be intermittent unless it has something to do with heat but normally the cable would only get hot when cranking if it's got a bad spot causing resistance. My bet would be inside the starter itself like mentioned above.

 

[mla2ofus]

I had the same problem on my '98 Force 90 HP. Finally took the starter apart, inspected everything and greased the shaft bushings. Has worked flawlessly for 5 yrs now. I think it was due to dry bushings.
Mike

 

[racerone]

A good starter will spin up instantly.----That acceleration of the armature throws the bendix up into the flywheel.-----These starters are elegantly simple to work on.---I install brushes on these regularly at $5.00 a set from local starter shop.

 

[cr295]

I don't know how a battery cable being bad would be intermittent unless it has something to do with heat but normally the cable would only get hot when cranking if it's got a bad spot causing resistance. My bet would be inside the starter itself like mentioned above.

I'm scratching my head on that one too??? The only common denominator I can come up with is that there may be a small nick or hole in the jacket of the cable and salt water is getting in there and in effect shorting or weakening the current or possibly that the cable has internal corrosion and as it gets jostled around while running this causes an intermittent good/bad conduit for the current??? The condition never exists at the ramp or on the hose, only after running in salt water for some time?

I might be way off base here but now that I sit here and think about all this, each time the slow crank condition occurred the water was rough that day and I took enough spray to wet the decks and probably soak the rigging tube/cable run. It never happened on a calm day.

One thing I do know is that when the condition happens, I jump the engine from the solenoid/starter to get it running and it cranks and starts without any hesitation. This leads me to believe that 12 volts are not making it all the way from the battery. It will not improve cranking speed or start the motor by jumping the battery itself.

If the starter or solenoid were weak or defective you would think that applying 12v directly from a jumper pack to them would result in the same slow cranking. When ever I do this the starter spins like no tomorrow and fires right up.

As others have mentioned the solenoid is cheap and the starter is easy to work on. I have a spare starter, so I will rebuild that. The existing cables are old so I thought what the heck quit being cheap, just replace them anyway! I will put the new cables in and report back. If that fails I'm on to the solenoid and then to the starter. I'm thinking about doing them in this sequence to positively determine the cause.

As much of a PITA that it is using the jumper box to get going again, it has never left me stranded. I guess I should feel lucky there.

Thanks for all of the suggestions and with Racerone's encouragement I'm now actually looking forward to an attempt at rebuilding the spare starter. I found the starter rebuild/brush pack online. Any other parts I should be getting for the rebuild?