How do you determine if Johnson 150 HP has S.L.O.W. system?

[newenglandguy]

I have a 1989 Johnson 150 HP (Model Number J150STLCEM) and would like to know how I determine if it has either the Quick Start option or the S.L.O.W (Speed Limiting Overheat Warning). Still struggling with finding out why I'm bogging down once I hit 3000 RPMs. According to some ignition troubleshooting link I found ( http://issuu.com/cdielectronics/doc...t.xml&backgroundColor=000000&showFlipBtn=true) it seems to indicate that if it was SLOW, it would bog down at 2500 - but I don't want to miss one detail.

 

[ohioriverat]

Re: How do you determine if Johnson 150 HP has S.L.O.W. system?

I just went through this on my 2000 70hp and it turned out to be a fuel clamp not being put on, on mine at the powerpack there was a yellow/red wire and when cranking the engine it would have 12v to this wire. that is the quickstart wire. i believe the slow is built into the pp and will reset sometimes..

 

[hidef]

Re: How do you determine if Johnson 150 HP has S.L.O.W. system?

I believe you have a GT150 based on the model number and it should have SLOW. You want to follow the troubleshooting steps on page 50 of the CDI guide. Follow the steps disconnect the sensors and see if it helps if it does then there is your issue. Also your alarm should be sounding if slow is engaging unless someone has disconnected it.

 

[boobie]

Re: How do you determine if Johnson 150 HP has S.L.O.W. system?

It has both Slow and Quick Start.

 

[newenglandguy]

Re: How do you determine if Johnson 150 HP has S.L.O.W. system?

hidef - it is indeed a GT150 - it's right on the cover. How do I figure out if the SLOW buzzer/circuit has been disconnected? At this point, I wouldn't put anything past the owner before me. I've got a SELOC manual for this motor, and still waiting for my Factory Repair Manual to show up - but the SELOC doen't seem to mention the SLOW system - at least it's not listed in the Master Index. Are the temp sensors those little plugs that are on top of the cylinder heads? One has one wire, the other has two. Do you disconnect each sensor, one at a time? Another thing that's bothering me about the potential that it is a sensor - mine happens at 3000 RPMs, not 2500 RPMs. Is that "close enough" or does it say it's something else?

boobie - what exactly does the Quick Start feature do? Please bear with me - this is my first boat, and I'm not even getting out of the starting blocks. Would it show up in the Electrical section of a manual (like SELOC) or would is show up under Fuel System?

Thanks

 

[newenglandguy]

Re: How do you determine if Johnson 150 HP has S.L.O.W. system?

I just went through this on my 2000 70hp and it turned out to be a fuel clamp not being put on, on mine at the powerpack there was a yellow/red wire and when cranking the engine it would have 12v to this wire. that is the quickstart wire. i believe the slow is built into the pp and will reset sometimes..

ohioriverat - what's "pp" - you say the SLOW s built in to it?

 

[emdsapmgr]

Re: How do you determine if Johnson 150 HP has S.L.O.W. system?

The SLOW system is part of the overheat warning system. When the powerhead heats up to 203 degrees and the hot horn activates, the power pack limits engine rpms to no more than 2500 rpm's to minimize powerhead damage and to permit the engine to continue to propel the boat to safety. It's covered in the factory service manual.

 

[Haffiman]

Re: How do you determine if Johnson 150 HP has S.L.O.W. system?

An easy way to see if an engine has SLOW, is to look at the power pack. If a Brown(Tan) wire is going into the pack, it has SLOW.
If the engine has a dual wire temp switch with a Black/White in addition to the Tan(Brown) going to the power pack, it has Quick Start.

 

[newenglandguy]

Re: How do you determine if Johnson 150 HP has S.L.O.W. system?

Haffiman - it has both - thanks.

How can I easily confirm the horn is working? When I get this bogging down at 3000 RPMs (at least according to the Tach) I do not get any horn/alarm. I do see there is a male/female plug on at least the one brown wire coming out of the sensor with two wires. Also, if one had to replace these temp sensors, how do they come out? They seemed to be "pressed" in to the hole in the head. I've seen some that have a hex head on them, but these are just round "plugs".

 

[Haffiman]

Re: How do you determine if Johnson 150 HP has S.L.O.W. system?

Test the alarm:
1: The alarm should make a short BEEP when ignition is ON.
This is only a horn function test!!
2: Start the engine, pull apart any of the brown alarm wires (temp or VRO tank), ground the end from the harness. The alarm should go off.
3. If grounding the VRO tank (low oil), this should not set off the SLOW function.
If grounding the Temp alarm, the SLOW function shall be activated.
If giving full throttle, do NOT turn off engine, depending of which wire/switch has been activated you will either get full throttle (Oil Level VRO tank) or limited if temp.
To re-set, turn off engine and restart.

 

[emdsapmgr]

Re: How do you determine if Johnson 150 HP has S.L.O.W. system?

Maybe you have a fuel issue. Have you tried constantly priming the fuel hose bulb when the engine is bogging? This will force extra fuel into the carbs. See what happens if you do.