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97 Johnson 90hp Bogs after sinking

R

reelmichigan

New member
Hello all,
New here hoping to find some help.
My buddy has a 97 Johnson 90hp 2 stroke outboard (J90eleuc) that recently sunk in fresh water (bad storm & bilge). Was submerged 12hrs tops. Now it won't go over 10% throttle without shaking and bogging.

I'll give everyone the steps as they occurred and maybe someone can make sense of it all.
We were able to re-float the boat, took out the spark plugs cleared cylinders of water, then drained the 2 top carb bowls and we couldn't reach the plugs on the bottom 2 bowls.
Put plugs back in and it won't start (feels like no spark) so we got a can of starter fluid to see if it would fire off with that so wed know if we had spark, no luck.
After some himing and hawing raising and lowering the trim and multiple times pulling the plugs cleaning them and emptying the cylinders of new water (from bottom carbs I assume) It fired up on the starting fluid and would run on high idle on its own fuel. We let it run like this for 30 minutes or so to clean the carbs out. Then it idled perfectly.
Went fishing after and it was running better than before it sank. Few days later we take it out again and during a run up river it started bogging almost like fuel starvation, I pump the bulb and notice a small leak at the bulb but the boat clears up and runs great. Noticing manipulating the bulb would change the engine tone I tell my buddy it's prolly just sucking some air and hell need a new bulb so we dock it and he gets a new primer bulb the next day along with fresh fuel and some treatment and new spark plugs.
Few days later he's out with his wife and it does the same bogging thing at 10-20% throttle it just rolls over and the motor starts shaking pretty aggressively. Now ruling out the bulb, plugs, and gas contamination we start to search else where for the problem.
At this time the boat will only do about 7mph normally does about 40. Motor shakes badly at that speed/rpm (no tach) let's say 1500rpms. This only happens under load! Boat will free Rev in neutral great with full range no shaking.
Another thing I noticed is when we are cruising over waves at that 7mph very rarely the motor will seem to start picking up rpms in a rhythmic lurching way and get upto maybe 2krpms and 10mph.
Attention has shifted to the coil packs I tried checking for spark by pulling the leads whial running, all 4 cylinders seem to have an affect on the idle speed. Along with hearing audible clicking when removed. Cylinder 1 wire bit me pretty good when I was holding it but none of the others did which I found odd. Possible bad wire?

What's my troubleshooting pathway here? My brain is screaming carbs and coils! I'm pretty mechanically Inclined but outboards are new to me. In research it looks like I need a dva tester to test the coils? All I have is a cheapo multimeter. Trying to avoid pulling the 4 single carbs to clean unless absolutly necessary, with it running great for a day after it sunk I feel like it's more electrical than carb related but idk.
Side note i checked tank vent, fuel flow, and fuel filter. Also pulled high flow jets from behind the carb bowl drains and they were clear, carb cleaned everything anyways.

Any help or guidance in where to go next without throwing a ton of $$$ at it would be greatly appreciated. My buddy just got this boat so I really wanna help him get it working again.
 
Did you empty contents of the OIL TANK ?----Possibly had water in it.-------System is happy to inject water.-----But bearings won't be happy.
 
racerone said:
Did you empty contents of the OIL TANK ?----Possibly had water in it.-------System is happy to inject water.-----But bearings won't be happy.
Click to expand...
Visually inspected oil tank after sinking, no signs of moisture and oil bulb was still firm. Should we clear that system somehow? After not finding water in the oil tank I assumed the system being under pressure kept any water ingress into that system.
I should add it was the rear of the boat that sunk and the gas tank is in the bow and never was submerged due to dock lines holding it above water. We mostly just treated the tank for anything remaining in the carbs or engine. We've also ran thru 10+ gallons of gas since sinking and we are on the 3rd tank of fresh gas. Mpg is horrible with the low power.
When plugs are pulled currently they are slightly wet/oily with gas/oil. Not soaked but not as clean as ide like to see em on say a dirtbike. Leading me to think weak spark/ incomplete combustion is occurring.
 
racerone said:
Checked for overheating ?----S.L.O.W system activating?
Click to expand...
Ok now this is interesting! So since the sinking the tell tail has been unusually strong, like it used to shoot say a foot with adequate pressure and now it shoots like 3ft and if you Rev the engine it shoots almost 10ft like a pressure washer with a zero tip. Was thinking it was a sign of a healthy impeller or some junk cleared out causing the increase in flow.
Could this be a sign of a clog in the cooling system somewhere? Perhaps it's bypassing the head and causing extra pressure at the tail? But tripping slow? I really have little idea how these systems work so bear with me.
I'm reading the SLOW system activates based off temp sensors in the head? I'm assuming it cuts spark or retards timing to limit heat in the system as a safety?

Is there a way to test the temp sensors? Or bypass to test functionality?

Would sinking cause temp sensors to go bad? The bog condition is consistent during cold or warm as soon as it's in gear it's limited power.

When in SLOW mode is the engine still able to Rev it's full range in neutral? The issue only arises in gear with load.

No signs of overheating when working on the engine during troubleshooting the plugs and head are warm but not to hot to touch. I don't feel like it's actually overheating but it could definitely be shorted or malfunctioning and thinks it is. I will take a temp gun with me and see what the heads are reading after running.

Did not know SLOW mode was a thing thank you for bringing it to my attention now I'm thinking coils, carb, slow for possible causes.
 
Stop revving the motor in neutral!----Not good for the motor.----Simple trouble shooting will find the issue with the motor.
 
racerone said:
Stop revving the motor in neutral!----Not good for the motor.----Simple trouble shooting will find the issue with the motor.
Click to expand...
Absolutly! Not something we are doing regularly just something I noticed during troubleshooting and found odd. I was thinking if carbs were clogged it wouldn't high idle or rev in neutral but it does so I ruled out carbs for a bit and started leaning towards coils.

I will search up testing procedures for the SLOW system and see if there's a way to bypass temporarily just to locate the issue. Fingers crossed that's it! Any ideas of other things to check or test?
 
Ok got out to the boat today to do some troubleshooting on the water, planned on testing the temp sensors and coils and also got some new coils to install if they were bad.
This issue only arises under load so I popped the engine cover whial my buddy drove and as soon as I started pressing and moving the sparkplug wires it erupted to life!
Standing at the rear of the boat looking forward it's the wire for the top right cylinder to the coil which I'm assuming is 3? 1 / 3
2/ 4? If this is the cylinder layout.

The issue is the clip or ring inside the coil side of the wire has lost its grip totally causing it to work its way mostly off giving weak or no spark. My question now is why would or could a single non firing cylinder make it run so horribly on a 4 cylinder? Like if the coil was bad and both cylinders it ran were non functioning that would make sense but just 1 out of 4? These are dual coil packs so 2 coil packs for 4 cylinders.
Low on power would make sense with a misfire but not 10% or 20% of normal power.

I read somewhere these coils are daisy chained essentially? Is that true? So if 1 goes bad it takes out 2 or somthing along those lines. They each have individual trigger wires (orange)and grounds so I don't see how one could affect the other but it definitely seems like when this wire comes unplugged we lose multiple cylinders spark. This is just kinda off feeling of how the motors running I haven't put a timing light or spark checker on to see if the other cylinders are actually losing spark when this one does.

Someone explain this for me lol
 
Went out today started right up idled for 3 mins and died, couldn't get spark back for a bit then it started and died again under 20% throttle. An instant cut off of power. Power pack? Stator? Any ideas
 
These are 2 separate coils in one assembly.-----They are not hooked together.----#1 is the highest cylinder on the motor.-----#4 is the lowest on the motor.
 
Last edited:
racerone said:
These are 2 separate coils in one assembly.-----They are not hooked together.----#1 is the highest cylinder on the motor.-----#4 is the lowest on the motor.
Click to expand...
The cylinders are V not inline
1/3
2/4 like this not sure If cylinder numbers are correct tho.

Getting a dva adaptor to start diving into powerpack,stator,optical ignition. Any help would be greatly appreciated I'm following cdielectronics troubleshooting guide for no spark.
 
I bought a pair of these 97 model 60 degree motors years ago to rebuild.----Have a few others as well.-----Look carefully at your motor !----#1 is the highest and #4 is the lowest.
 
racerone said:
I bought a pair of these 97 model 60 degree motors years ago to rebuild.----Have a few others as well.-----Look carefully at your motor !----#1 is the highest and #4 is the
Click to expand...
Ah I see the 2 banks are slightly offset leftside being slightly higher
So is it 1/3
.............2/4 or
1/2
3/4?
This is so frustrating we have 0 spark now after the last time it died, moved the bad wire, replaced the coil pack no change. It's like there's a main issue causing loss of spark intermittently (now perminately) and then the bad plug wire was making it run bad even when it had spark. The day I wiggled the plug wire it came to life and ran perfect. But now it has no affect, I've tried wiggling other wires to see if it's a bad ground or connection nothing changes. Buddy is getting the dva tester tmrw and we are gunna start working our upstream from the coils and test whatever we can.
Is there a good way to test the kill circuit? It tried to fire off for a second after we had messed with the safety lanyard so I'm suspicious of that circuit.
 
Ok update,
We went out to troubleshoot and discovered a yellow/red wire on one of the powerpack 4pin connectors had come unpinned and I could see the weather seal so it wasn't seated enough to make contact! Thinking surely this was the source of all the problems I reseated it and put the motor on muffs to test for misfire.
It started right up which was promising because when we left the boat last we had no spark.
On muffs in neutral runs smooth(no misfire)
On muffs in gear runs smooth(no misfire)
Time for the lake!
Nope as soon as the engine had load and backpressure the misfire under load is still present :(
Time for testing!
Attached an inline spark tester to cylinder 1, it showed good constant spark at idle and a misfire became obvious under load sometimes the light would black out completely and the spark in general was dimmer or weaker overall under load.
Tested all 4 cylinders this way 3/4 had bad misfires and 1 seemed more consistent but still misfiring.

Decided to start at the stator and work downstream and see where the power is dropping out. Testing with a dva meter and using cdielectronics troubleshooting guide I found this.
TESTING WHIAL IN NO SPARK CONDITION
*Disconnected black/yellow stop wire from powerpack no change.
*Disconnected 2 yellow wires from stator to rectifier, no change.
*Connected external battery pack to test for voltage drop during cranking, no change
*Engine is running forwards not reversed
*Checked powerpack/ignition grounds (shared location) for corrosion, none
* Disconnected 4 pin port side connector on powerpack(yel/red, bl/yel, tan, wh/blk) no change
** Step 9. "If it loses spark when key is disengaged, check dva voltage at stator orange to orange"
I'm assuming this is meaning If the key can kill the engine whial running and when the 4 pin plug is disconnected? If so.. the key would not kill it due to the kill wire being in that plug.
* skipped optical sensor cleaning FOR NOW

*STATOR TESTS
This is from stator to powerpack

Brown to brown yellow Resistence=1000ohms (900-1200) in spec
DVA disconnected 275v(150-400v) in spec

Orange to orange/black 55ohms (45-65) in spec
DVA disconnected 65v (45-120v) In spec

I was hesitant to test "connected" values due to having to peirce the wires to test. I can do that if necessary olease advise. I know a voltage drop when connected could point directly to the powerpack being faulty but I want to explore other components before piercing the wires.

I moved on to the optical sensor wires coming from the power pack going to the sensor.
*Step 15 test orange/red to engine ground 0v (10.5-12vdc) No power at all going to this wire could this be the smoking gun??
Now it says test black/orange to engine ground but it has a warning directly under the specs that says
"the black/orange should NEVER be shorted to engine ground as this will damage the sensor"
So im admittedly confused with the contradiction in the instructions. And also when testing this plug the sensor would be unplugged from the connector so it isn't in the circuit to get burnt out? Or am I thinking about this all wrong.

Fingers crossed tommarrow we have spark again and I'm thinking if that orange/red now has voltage that the issue lies in the power pack due to the coil testing good it is supplying power to the pack but the pack is not outputting. And rectifier seems to be working but does have some cracks in potting resin.

* I also tried disconnecting both temp sensors to test if it was in SLOW but I've decided the random misfire has no rhythm to it like I've seen SLOW do. Is disconnecting the sensors the proper testing procedure? I also saw another guy ground it to the block and his problem fixed but I wasn't sure if that was proper for this engine?

* bonus info when engine is running
Pushing key in (choke) chokes the engine out under load.
Pumping bulb doesn't improve condition
Clean tank
Clean carbs
New coils
New plugs
Moving around wiring (plug/coil wires, grounds, powerpack harness, recifier harness, stator harness) does not change running condition making me think this is a degradation of some curcuit under heat or use and not a loose/ corroded connection.

Please advise on best course of action from here and any additional tests I should perform as im about at the end of the cdielectronics troubleshooting checklist.
As of now powerpack is #1 suspect



racerone said:
I bought a pair of these 97 model 60 degree motors years ago to rebuild.----Have a few others as well.-----Look carefully at your motor !----#1 is the highest and #4 is the lowest.
Click to expand...
Exact engine we are working with! The 60deg!
 
racerone said:
I bought a pair of these 97 model 60 degree motors years ago to rebuild.----Have a few others as well.-----Look carefully at your motor !----#1 is the highest and #4 is the lowest.
Click to expand...
Since it sank the telltale has been abnormally strong and one head is warmer than the other im concerned there may be a clog in the head somewhere causing the higher backpressure.
Do you think this is possible? Do you know of a way to clear out the water passages in the head? Can I blow compressed air in the telltale or is there some service ports I can open at the top of the heads or anything?
 
racerone said:
Perhaps the S.L.O.W. protection circuit is kicking in.----Remove thermostats.----Start motor.----Observe waterflow.
Click to expand...
Alright will remove thermostats next time engine is running and check for adequate or equal flow from both ports. What would the proper way to bypass the temp sensors temporarily to deactivate SLOW be? Can't find a video or forum on this engine on how to bypass but I've seen other Johnsons that people either disconnect the barrel plugs on each sensor or ground out one of the wires to test if SLOW is active.
I should also mention this misfire under load is present right at startup with engine cold. SLOW would be stuck on all the time if that is the issue. A quick bypass and check would be a nice option if possible
 
Confirmed when motor has spark the orange/red wire going from the powerpack to the optical sensor has almost 13v (10.5-12vdc) is the recommended range so a little out of spec.
Powerpack ordered should be here in a few days
racerone said:
Perhaps the S.L.O.W. protection circuit is kicking in.----Remove thermostats.----Start motor.----Observe waterflow.
Click to expand...
Removed thermostats, they screw into a blind hole with no water flow but i found a brass plug fitting on each head that does access the coolant system. Had good flow at the head so gunna chalk up the uneven heat to the misfires for now, will revisit once motor is running normal on all 4
 
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