1993 johnson 150 will not run over 3500 rpm

I am new here and have searched this problem out but no clear answer as it probably is not one. Motor is a 1993 johnson silver series model #vj150elatr. Here is problem crank motor let warm up for minute or two give it full throttle engine runs fine(5000-5200rpm) but come off plane and idle for a minute or two give full throttle again, wont go past 3500 rpm and motor skips violently. Feels like a rev limitter in a car. Shut the motor off let cool for 15min or so motor will work fine until you return to idle for minute or so then the problem recreates itself. I feel that it must be heat/electrical related. Here is what has been done so far. Compression check around 95 even across all cylinders. Carbs flushed and jets cleaned out(not rebuilt) champion plugs installed(QL78YC) gapped at .030. Timing checked, engine spark checked, power pack replaced, new fuel line from tank to front of motor, new fuel filter, new priming bulb, new filter going into motor(internal filter). I have a great stream coming out of engine and this engine will idle smooth for as long as i have wanted it to. I have not checked my alarm so know that needs to be checked that leads to next question what is the best repair/service manual or manuals for this boat?? I want to get them so i can fix this it is driving me crazy. I know this boat past owner fished many times out of this boat did not do this last year. Another problem is the starter. It has been checked to be fine. Only does on the first start of the day. When you turn the key all you here is what i believe to be the bendix spinning. This starter has a fixed gear on shaft so i guess the gear has to spin down to it to turn the flywheel. Once you do get it to catch and fire usually won't happen the rest of the day but don't want that to leave me stranded. Thanks for any help in advance but really want to know what is the best manuals to buy.

Re: 1993 johnson 150 will not run over 3500 rpm

Good ,
first get the real factory service book, its worth every penny. Accept no substitutes.!
www.outboardbooks.com

The buzzer should beep when ignition is keyed ON, that needs fixing first.
Make sure you get 12v at the buzzzer purple wire when ig is ON, brown wire is signal, bl ground.

Remove + wire from battery, then go to the starter and remove+ wire and clean conections bright and shiny, do the other terminals.
No thumbscrews allowed at the battery terminals. It kinda sounds like the solenoid. You can get rebuilt starters on ebay a lot cheaper than OMC parts.

On the running, its going into SLOW mode, one bank shuts down due to overheat, the powerpack gets triggered by the heat sensor in the heads and terminates 3 cyls. When ignition is turned off it resets. You're basically beating the snot out of it, its going into SLOW to protect itself.

Thats the optical ignition system right?
It needs going through, rebuild all carbs with new carb kits.
Get a cheapo infra red thermometer and shoot the heads to find if its overheating.
I got one for $9 at harbour freight, home depot probably sells them too.
Its probably gonna need thermostats but first ascertain that its actually overheating.

The alarm system has to be working before taking it out again.

Re: 1993 johnson 150 will not run over 3500 rpm

okay excuse for my ignorance, motor does chirp when i turn switch so i know that works i should have been more clear on that. I was more worried about a sensor being bad and not alarming. This is the reason i am getting the book. I don't know what optical ignition means so there again need the book. The starter thru me off with the fixed gear on top. It doesn't spin up to the flywheel like all other starters i have seen. In the dark on that. so you think the thermostats not operating properly is making it overheat. Someone else has told me it was going into slow mode but couldn't give me an explanation of why. Thanks for the info, can't wait for the book to get here.

Re: 1993 johnson 150 will not run over 3500 rpm

CDI electronics has a great troubleshooting guide for free.. very helpful

Re: 1993 johnson 150 will not run over 3500 rpm

Thanks, is that cdi electronics.com??

Re: 1993 johnson 150 will not run over 3500 rpm

http://issuu.com/cdielectronics/doc...t.xml&backgroundColor=000000&showFlipBtn=true

Re: 1993 johnson 150 will not run over 3500 rpm

alumacraftmvtek said:

okay excuse for my ignorance, motor does chirp when i turn switch so i know that works i should have been more clear on that. I was more worried about a sensor being bad and not alarming. This is the reason i am getting the book. I don't know what optical ignition means so there again need the book. The starter thru me off with the fixed gear on top. It doesn't spin up to the flywheel like all other starters i have seen. In the dark on that. so you think the thermostats not operating properly is making it overheat. Someone else has told me it was going into slow mode but couldn't give me an explanation of why. Thanks for the info, can't wait for the book to get here.

Click to expand...

So the beeper works on the self test but you're not getting the overheat alarm. ?
Test the heat sensor by unplugging the port sensor and grounding the power pack side of the wire to the block, the heat alarm should sound.
You haven't verified that its actually overheating. The thermostats could be fine.
Verify temp withy infra red thermometer, shoot the heads.

The power pack will put it into SLOW for a few reasons,
an actual overheat.
A bad heat sensor.
sensor wire touching a sparkplug wire triggering the false signal.
Low oil warning.
Faulty powerpack.

Verify its actually going into SLOW with a timing light, the port side bank should shut down if its in SLOW(no spark).

This is the CDI Optical troubleshooting section in an easier to follow format.
http://www.maxrules.com/fixomcoisignition.html
You have the Optical ignition (OIS.)

Re: 1993 johnson 150 will not run over 3500 rpm

alumacraftmvtek said:

okay excuse for my ignorance, motor does chirp when i turn switch so i know that works i should have been more clear on that. I was more worried about a sensor being bad and not alarming. This is the reason i am getting the book. I don't know what optical ignition means so there again need the book. The starter thru me off with the fixed gear on top. It doesn't spin up to the flywheel like all other starters i have seen. In the dark on that. so you think the thermostats not operating properly is making it overheat. Someone else has told me it was going into slow mode but couldn't give me an explanation of why. Thanks for the info, can't wait for the book to get here.

Click to expand...

This thread should help explain your starter question.
http://www.bbcboards.net/zerothread?id=662215

One thing, if your engine is popping but not firing (flooded) then it will throw the bendix out of the flywheel gear and you'll just hear it winding down.
You may or may not be experiencing that.
If it does it repeatedly , take the shifter out of gear and open the throttle and crank to clear the cyl's ,when it fires shut the throttle down to idle.
My mechanic showed me that one, its important to know how to clear the engine if you flood it and need to start the engine to get out of danger.
It happened to me when I was scooting along and leaned against the ignition key, that flooded it and I was drifting toward rocks.

Re: 1993 johnson 150 will not run over 3500 rpm

My starter you can hear something spin but wont spin flywheel. Eventually it will work and after it cranks i don't have anymore trouble during the day, just that first start up. Just that starter with gear that doesn't spin up to flywheel is throwing me off because i don't know exact operation of it. but will figure it out. Thanks for all of the help everyone is giving me. I spent to much for a mechanic that did not fix a thing so i am gonna do it myself and know it its done right. Thats a story for another thread.

Re: 1993 johnson 150 will not run over 3500 rpm

yes jonesg the self test works but never get an alarm i am gonna check over wiring this weekend and try to find those sensor wires. waiting for manual to get here so if i have any doubt i can find what i need, i have to work around my wifes schedule we have a 3 yr old and one on the way so work on it when i can.

Re: 1993 johnson 150 will not run over 3500 rpm

Heat sensors are right in the cyl head with a single tan wire, it runs right next to spark plug wires and cross firing can happen, there is a bullet connecter in the wire, seperate that and ground to the head. That test is for the circuit, not the sensor itself. Sensor is tested in a pan of hot water and meter.
You'll find it all in the book, have a good read and it will all become less myserious.

Re: 1993 johnson 150 will not run over 3500 rpm

checked my circuits this weekend unplugged tan wire and grounded to the engine block and heard the buzzer so i know circuit is good. gonna wait till service manual gets here before i take sensors out don't want to mess anything up. thanks to everyone for their help will definitely reply back when i figure problem out.

Re: 1993 johnson 150 will not run over 3500 rpm

I thought SLOW limited RPMs to 2500..not 3500. You need to do the test outlined in the link I provided. If everything checks out with the electronics you have a fuel issue. I assume you have done a compression check.

Re: 1993 johnson 150 will not run over 3500 rpm

had a compression test done tested about 95 evenly across all cylinders. now dont know if this will make a difference, probably will but my tach rest at 1000rpm even when off so with that said could me thinking it is at 3500rpm really be 2500 rpm since it already reading 1000rpm off??

Re: 1993 johnson 150 will not run over 3500 rpm

When its idling is it idling at 2000?

Re: 1993 johnson 150 will not run over 3500 rpm

alumacraftmvtek said:

had a compression test done tested about 95 evenly across all cylinders. now dont know if this will make a difference, probably will but my tach rest at 1000rpm even when off so with that said could me thinking it is at 3500rpm really be 2500 rpm since it already reading 1000rpm off??

Click to expand...

Tachs often read some rpm when off but should zero out when key is on.

Re: 1993 johnson 150 will not run over 3500 rpm

also does your tach appear to be working properly?? (the rest on 1K with key off is normal)..You will still need to test all of your electronic parts, do not stop just because you find one bad part..test entire electronic system. Again as per link provided in my first post.

Re: 1993 johnson 150 will not run over 3500 rpm

ok finally getting chance to work on the problem. i did find a fuel leak on right side of motor(standing behind boat) it was approx 1/8"black hose. There are 3 of these on that side looks like one goes to each cylinder. Fixed that leak did have temp sensor wire touching spark plug wire on right side also(single wire temp sensor). My big question is i pulled the thermostats out. When i pulled the one out on the right side it came out in one piece.(spring and white plastic type case) when i pulled the left side out the white plastic case had came apart at the top seam. Meaning i had spring and white cap that spring sets against in one hand and the other hand i had the bottom of the white case and the actual thermostat in that hand. I am gonna replace both of them since i have them out but could that broken case be causing my thermostat not to work correctly?? Maybe causing all the problem i have been having?

Re: 1993 johnson 150 will not run over 3500 rpm

i did check with infared thermometer before pulling thermostats out boat had been at idle on garden hose for about 10min. Right side read average 140-150 across all 3 cylinders on the left side it read around 110 average across all three cylinders. the left side is the side that the white housing around thermostat had seperated.

Re: 1993 johnson 150 will not run over 3500 rpm

I finally fixed it, it was the thermostat that was cracked, i guess it wasnt letting that side build up enough heat and the other side was doing double duty and it was causing the problem. Fixed the other problems i found wrong also but checked that it was the thermostat first before fixing the other problems on it. Thanks for all the help you all gave.