1989 johnson 120 runs 2500rpm at full throttle

[buggyman20]

Re: 1989 johnson 120 runs 2500rpm at full throttle

I will check the starvation issue. Is there any way to check a power pack without having special equipment. The service manual calls for a neon test light. Can you check without that?

 

[SparkieBoat]

Re: 1989 johnson 120 runs 2500rpm at full throttle

if you are running exactly 2500 rpms max..i would just replace the power pack with a new CDI one. specially if its the original one

 

[reeldutch]

Re: 1989 johnson 120 runs 2500rpm at full throttle

could also be a real overheat condition, or faulty temp switch.
we cant tell until you run the motor in the lake or bay and duplicate the problem.
check the temp with a temp gun.
check vacuum on the fuel system
check fuel pressure

by eliminating things we could point at the powerpack.


go ahead and buy a new powerpack there only about 200 dolllars. and you can not return them.so thats up to you.
it could not solve the problem .
run some tests so you know in wich direction you have to go.

 

[SparkieBoat]

Re: 1989 johnson 120 runs 2500rpm at full throttle

I would make sure you are not having an over heat problem first. but here is your power pack..I recommend the CDI, here is the best prices I found
http://www.boatfix.com/bykeywordnew2.asp?textfield=18-5772&texttype=2
http://www.georgiawatersports.com/P...base&cvsfa=2150&cvsfe=2&cvsfp=LNS-667-1134041
http://www.marineengine.com/newparts/part_details.php?pnum=CDI113-4041

 

[jonesg]

Re: 1989 johnson 120 runs 2500rpm at full throttle

I will check the starvation issue. Is there any way to check a power pack without having special equipment. The service manual calls for a neon test light. Can you check without that?

What service manual?

Go here and get the right one before you drop a lot of money throwing parts at guesses.

www.outboardbooks.com

The problem could be the VRO too, no oil alarm throwing the PP into SLOW, if you buy a new PP and you still have the problem you're minus $200.!

Get the right manual and do the troubleshooting proceedures to find the exact source of the problem.

 

[buggyman20]

Re: 1989 johnson 120 runs 2500rpm at full throttle

I checked both temp sensors and they make the horn go off when grounded out as listed in the repair manual. I have a repair manual on cd. It mentions a s-80 neon test light to check power pack. I was wondering if there is any other way to test it. These lights are not cheap. I am going to try to check temp this weekend.

 

[SparkieBoat]

Re: 1989 johnson 120 runs 2500rpm at full throttle

If it is not over heating, you got good compression, spark is good on all cylinders, no problem with fuel delivery, carbs are clean and working properly, spend the $150 on a new CDI Power pack..even if your wrong you still got a new power pack ( and thats not a bad thing) with a spare for testing. make sure your wire connection coming from your VRO is disconnected to prevent low oil alert from putting it into slow mode. I especially think it is PP because of it being 2500rpms exactly with no surging.

 

[SparkieBoat]

Re: 1989 johnson 120 runs 2500rpm at full throttle

the Sierrra one is $100 but I would spend the extra $50 for the CDI

 

[buggyman20]

Re: 1989 johnson 120 runs 2500rpm at full throttle

I have looked over all the posts. I am going to run a line directly from one tank to the motor and make sure the vent is working on the tank. Also I am putting a temp gauge on one head to see how hot it gets. I have fresh gas to eliminate that problem. I checked my records and the impeller was put in 9-27-07. I have not ran it much since then so I hope that is not the problem but if it is that is cheaper than a pp. Thanks for the help I will let you know what happens.

 

[SparkieBoat]

Re: 1989 johnson 120 runs 2500rpm at full throttle

it is time for an impeller change anyway, go ahead and replace it.

 

[buggyman20]

Re: 1989 johnson 120 runs 2500rpm at full throttle

What is the normal operating temp range for a 1989 120 johnson?

 

[nymack66]

Re: 1989 johnson 120 runs 2500rpm at full throttle

My 87 140 v4 runs 125 to 130 range Port side and 135 to 140 on Starboard at WOT when trolling both sides increases by 5 to 8 degrees. I have two gauges and individual temp senders to each head.

 

[buggyman20]

Re: 1989 johnson 120 runs 2500rpm at full throttle

I just installed a temp gauge. At a fast idle the temp meter got up to 160. Can you tell me how to check the sensors that are in the head? The buzzer has never sounded. The buzzer works, I have checked it. I need to check the sensors.

 

[nymack66]

Re: 1989 johnson 120 runs 2500rpm at full throttle

I just installed a temp gauge. At a fast idle the temp meter got up to 160. Can you tell me how to check the sensors that are in the head? The buzzer has never sounded. The buzzer works, I have checked it. I need to check the sensors.

I am assuming you do not have a manual since this is covered under temperature switch test.
U need to do a continuity test using a ohmmeter connect one end to the wire the other to the metal portion of the switch.
The manual calls for using engine oil and slowly apply heat I personally will use a pot of water on a stove. Slowly heat it and you will see continuity at around 200 + 6 degrees turn off the heat as the temp decreases the switch will show NO continuty at around 175 degrees
If the switch does not react as mentioned replace it ..Check flea bay good bargains on NOS also the fact this puppy works in 175/200 range is the sole reason I like a water pressure gauge and good old temp gauge.

 

[buggyman20]

Re: 1989 johnson 120 runs 2500rpm at full throttle

I have a couple of questions. The service manual says you can unscrew the two halves of the therm housing. Do you need a special tool? Look like it has notches in it. Also I noticed a small drip around the water control valve. Can not tell if a hose is loose or the valve is leaking. What do you know about this valve? Thanks

 

[tal]

Re: 1989 johnson 120 runs 2500rpm at full throttle

You don't need a special tool to unscrew the vernatherms. The first time I saw them I thought you had to replace the whole plastic mess. I began twisting carefully and the two pieces came apart. It's threaded fittings.

 

[buggyman20]

Re: 1989 johnson 120 runs 2500rpm at full throttle

Can you tell me what the water pressure should be at idle and wot? What would be a good pressure gauge to buy?

 

[buggyman20]

Re: 1989 johnson 120 runs 2500rpm at full throttle

Where is the best place to hook up a teleflex water pressure gauge? The instruc. do not tell you a lot of info.

 

[buggyman20]

Re: 1989 johnson 120 runs 2500rpm at full throttle

I installed a new impeller today. The housing grommet had small cracks at the top of it but they did not go all the way through. Should I get a new grommet? I also back flushed the water lines and everything came out clear and clean.

 

[buggyman20]

Re: 1989 johnson 120 runs 2500rpm at full throttle

Finished impeller and water pressure gauge. Put on muffs ran it about 10 min. The temp stayed between 160 and 175. The pressure was around 10. Need to go to the lake and see how it runs.