2000 90hp Johnson Won't Start after Hot

[CincyCichlids]

Hello Friends,
I've already read through all off the posts I can find on this, and I hope that when I give you my scenario with all the information I can.. you can help (most of the previous posts have lots of missing information and don't seem to lead anywhere).

This is a Salt Water 2000 90HP Johnson
Very Low hours
Just had the Fuel Pump replaced withOUT the VRO (by choice)
The Carbs were also professionally cleaned
The model is the J90VLSSE.

When cold, the engine cranks easily and starts easily. It runs like a top. We take it out for 20 min or so, then we cast net for bait.. this means low idle, forward and reverse, etc with NO problems. We then take her out for another 20-30 min ride to a fishing spot and shut the engine off. When it's time to leave, it will crank fine, sputter and die. If we give it gas (neutral throttle up) it will chug for a second and then idle fine.. almost as if it has to beat a certain RPM to run fine. However, it will usually die when you reduce throttle to shift into gear. To get it going again, you need to get it to the point where it's starting to run and quickly push it into gear so it once again can beat that RPM and begin running fine again.

So what do you think this is? The coils are reacting from the heat? It's not the starter as it operates fine. The fuel lines are fine and have been replaced, it's not sucking in air anywhere. We have tried pumping the bulb that doesn't affect it. Should I test spark once it's not firing to see if there's a spark issue? Perhaps a voltage meter?

Please let me know if there are any other questions you may have that can help diagnose this.

Thank you

 

[Joe Reeves]

Re: 2000 90hp Johnson Won't Start after Hot

Yes, by all means, do a spark test.

Does your engine have a tachometer, and if so, has it been acting up? You spoke of the rpm a few times but didn't actually mention what rpm.

The stator on the 90hp model is a sealed unit under the flywheel which is a dual purpose component. A series of small hidden coils on each side of the stator pertain to the battery charging system. There are also two large hidden coils at the extrene front and rear of the stator which provide approximately 300 AC volts to the powerpack, needed to energize the ignition (spark).

Should either of these two large coils start to melt down, that area of the stator will crack and a sticky looking substancee will be dripping down on the powerhead area. This results in a voltage drop to the powerpack, in turn resulting in weak, erratic, and eventually no igniton.

The start of this problem usually results in having the stator and ignition acting normally when cold, but when hot, it's action is abnormal. Shutting the engine down, all engine heat rises to that stator area.

This may not be your problem but it is where I would start trouble shooting.

 

[CincyCichlids]

Re: 2000 90hp Johnson Won't Start after Hot

Joe,
Thank you for your response. The boat does have a tach, but I haven't looked at the rpm closely.. It hasn't done any jumping or erratic behavior to warrant a close observation. Mostly it's by sound.

I spoke with a mechanic today and he said that it could be an issue with the needle seats being worn out from the alcohol in the fuel. He said he'd recommend looking there first and change them out. He also said it could be too much fuel pressure from the new fuel pump (which I would find it hard to believe).

I will test to see if there is a low or no spark issue (indicating coils?) once warm, as well as to see if any fuel is leaking when I turn the motor off after it's warm (which he said was indicative of leaking needle seats).

Let me know what you think.

Thank you

 

[Joe Reeves]

Re: 2000 90hp Johnson Won't Start after Hot

You've already said that the engine runs like a top at first, and that the engine doesn't act up until you let it sit awhile...... water drains out of the powerhead, heat rises, etc.

Carburetors are not intermitent. They are either faulty or they're okay. If the problem was with the carburetor(s), the problem you speak of would be constant.

Fuel pressure? In all of my experience, I've never encountered a problem of that nature. However, remove the carburetor face plate and pump the fuel primer bulb up hard. If fuel flows from any carburetor, rebuild that carburetor. This would be a float needle valve problem, not a pressure problem.

Did you inspect the stator? If not, do so.

Another thing to check. There is a black/yellow wire leading from the ignition switch to the powerpack (kill circuit). Disconnect it from the ignition switch "M" terminal when this problem arises. If the problem ceases to be, replace the ignition switch as it has developed a intermitent short. Note that with this wire disconnected, it will be impossible to shut the engine down with the key.

With that black/yellow wire still disconnected, attach a volt meter set to its lowest reading or ammeter between the related "M" terminal of the ignition switch and any ground. Turn the key to the ON position (engine NOT running). There should be absolutely NO voltage registering. If even a microvolt exists, replace the ignition switch. Any voltage applied to that black/yellow wire will destroy the powerpack within a short period of time.

 

[CincyCichlids]

Re: 2000 90hp Johnson Won't Start after Hot

Joe,
Interesting theory on the carb being a constant issue.. so it's likely not that because it runs perfectly well until it's turned off.

I can't check anything yet as I'm currently in Cincinnati and the boat is in Charleston but sometime soon I'll be back down there. I'd like to go there armed with a huge checklist of all possible things. It's frustrating b/c at the dealership.. the motor obviously runs fine... and it wasn't run long or hard enough to create this issue.

You said the stator is hidden below the flywheel.. is there any easy way to inspect it? Just remove the flywheel..or?

Thank you again!

Chris

 

[Joe Reeves]

Re: 2000 90hp Johnson Won't Start after Hot

I retired a few years before that engine was manufactured so I'm not familiar with its design. The previous models..... you could simply look under the flywheel at the stator and if either of those large coils was melting down, dripping, it would be obvious. If this has changed, then removing the flywheel would be a must.

 

[CincyCichlids]

Re: 2000 90hp Johnson Won't Start after Hot

Joe,
Back down south here, took the boat out today. Started up just great, ran out about 5-10 miles perfect. When I went to shut it down, I let it idle for about 10 minutes to allow it to cool down. Went to start it, and it was fine. Took it back to the ramp, and when I tied it to the dock shut it off (not thinking) and then it would start for a few seconds, sputter and die. If I gave it throttle it would push the boat a few feet and die. If I gave it just throttle (not into gear) it would begin to bog down and then rev up quickly.

I did find on the boat parts they replaced. First, both thermostats - the middle plungers were popped out. I also found a heat sensor from the starboard side of the motor which looks like it had gotten really hot and melted some of the wires and the rubber gasket. This is alarming to me, however, by the way the motor runs perfectly at first, with quick throttle response and idles well, I do not believe there is anything severely wrong with this motor.

I tried to find the stator/flywheel however, the flywheel is completely covered in a shroud. I took off the first part and found that it is buried under timing parts, etc. So it would've taken much more time to remove the timing components to remove the shroud.

So when it dies, it simply seems like it's losing fuel. If I did the "turn to run, it'll beep and give it an eight count" it seemed to start much better and allow me to shift it into gear better. That makes me think it's a fuel issue. Could it be a power pack?


With this information, could you give me a list of what to check for? The spark plugs looked pretty good, one seemed a little wet but not too bad.

Thank you again,

Chris

 

[Joe Reeves]

Re: 2000 90hp Johnson Won't Start after Hot

The flywheel/stator setup you described (shroud, etc) on that engine is foreign to me. Obviously the progress in design in the few years since I retired unfortunately exceeds my knowledge. Anything I might say from this point on would simply be guess work and might lead you down the wrong path. I don't want to chance that.

I'll pass this along to some of the other members who would have full knowledge of that engine's design and circuitry. I'm sure they'll be along shortly. Sorry I couldn't be of more help.

 

[bob johnson]

Re: 2000 90hp Johnson Won't Start after Hot

sounds like he has a motor with OIS ignition.. the top of the motor is covered with timing components, one of them being an optical sensor, they have made them since 1995

bob

 

[CincyCichlids]

Re: 2000 90hp Johnson Won't Start after Hot

Bob,
Yes it is Optical Ignition, I probably should have mentioned it... have any ideas why it's acting up?

 

[bob johnson]

Re: 2000 90hp Johnson Won't Start after Hot

I am an electical incompetent.....

sounds like a few issues that guys have had with the warm maotor evaporating the fuelin the carbs....

but once a motor starts to run id think that issue would be cleared up...

some guys have suggested to not just shut down so quickly , let the motor cool and make sure there is a fresh shot of gas into the carbs when you shut it down( squeeze the primer bulb.


over heating electrical issues requires attention to well planned step by step test to make checks..

can be a slimy eel!!

bob

 

[Haffiman]

Re: 2000 90hp Johnson Won't Start after Hot

Dropping a comment on request from another poster:
There might be a couple of reasons for this problem.
1:
Ignition.
Your stator may be on its way to 'quit'.
The heat build-up when shutting down will reduce the charging capacity of the stator at cranking speed.
This may have effect on both the optical sensor and power-pack.
Do a cranking voltage output test on the stator both at cold engine and when the problem occurs. I have no books anymore, but think to remember the critical limit is about 230 Volts.
I have had cases where stator, power-pack and optical sensor had to be changed to rectify this problem. Individually tested they all 'passed', but together did not work.
Fuel:
Vapor lock.
Check the vapor chamber and the vapor pump. Leaking gasket between chambers and/or defective membrane in the pump.
However most likely the ignition is the problem.
During ignition testing, remember to disconnect the black/yellow wire from the power pack (stop circuit).

 

[CincyCichlids]

Re: 2000 90hp Johnson Won't Start after Hot

Haffi,

Thank you so much for helping out here. Although I'm not a novice, I'm not sure where I need to test these parts individually... I know you said you don't have any books, but how do I test the output from the stator?

Thank you,

Chris

 

[Haffiman]

Re: 2000 90hp Johnson Won't Start after Hot

Pull the plug going from stator into power pack, hook up a volt meeter (AC peak reading) and crank.
Unless you want to throw money in the sea by sending off to a 'swapping' mech, invest in an OEM manual.
For testing the optical sensor, you may need a OEM 'ignition analyzeer', which is a bit expensive. However if you have a friend running an alarm company and with an IR sensor tester, that may do.
An ignition lamp with rpm counter included is also an advantage. Hooked to the plug wires, any, you may check if you loose ignition to the plugs at higher rpm. A multimeter with an inductive sensor cable around the plug wires does the same.
Try a search at e-bay, Marine Engine or your local dealer, whoever gives you the best offer for the correct (ref mod number) manual.

 

[CincyCichlids]

Re: 2000 90hp Johnson Won't Start after Hot

I'm looking for a manual on this.. but for the meantime a couple more questions. What RPM should the motor be idling at? I believe it was around 700 rpm last night.. which seemed a little low to me. Any chance that increasing idle speed 200rpm or so may help? If so, how does one increase it?

 

[bob johnson]

Re: 2000 90hp Johnson Won't Start after Hot

I'm looking for a manual on this.. but for the meantime a couple more questions. What RPM should the motor be idling at? I believe it was around 700 rpm last night.. which seemed a little low to me. Any chance that increasing idle speed 200rpm or so may help? If so, how does one increase it?

book says 600-700 in gear!

bob

 

[Haffiman]

Re: 2000 90hp Johnson Won't Start after Hot

As mentioned, idle should be about 650, in gear forward, boat not tied up but running 'free'.
Depending on boat size, prop etc it normally gives about 900rpm in neutral.
Idle is adjusted by moving the LOW tab on the bracket that holds the optical sensor. Top stb side of engine if remembering right.
May I even suggest you do a compression test on engine both hot and cold.