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1997 J150 Suddenly Idling Too High

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lrycroft

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I have a J150 Ocean Runner (J150NXEUE) that suddenly started idling at 1300rpm. Nothing in the manual's troubleshooting guide covers this and I hope someone has experienced this before. The boat mechanic said it was probably the power pack, so I changed it. Same problem. I have checked the plugs and they look normal. I did find a loose hose and a cracked manual lever on the primer solenoid and changed them, but nothing else obvious. When I checked the timing in neutral, it showed about 8 degrees ATDC. Something that did happen prior to this was cruising at 3000rpm for about four minutes, the motor suddenly started shaking violently. I immediately backed off the throttle and it smoothed out at 2800rpm. I crawled back to the slip at 1100rpm and it's been idling at 1300 ever since. Any ideas?
 
sounds like it went into SLOW mode for it to be shaking like that. Did you have any alarms? When you say the motor is idling at 1300 RPM, is that on a hose or in the water?
 
Thank you for responding so quickly coueytwo. The idle at 1300rpm is in the water, in neutral and there were no alarms. Before the high idle started, I took it out again the next day to see if the same thing happened and it did. After about four minutes of running smoothly at 3000rpm, the shaking started again. Except this time, when I went to idle in forward, it wouldn't go below 1300rpm. I came into the slip a little hot but had no choice. It ticked the neighbors off a bit until I explained what happened. It wouldn't come out of gear until I almost had it in reverse.
 
Do you think the motor is overheating? I ask this because it sounds like its going into SLOW, I need you to check the temp alarm warning system.
How to check your warning horn.
1. Disconnect bullet connector at temperature switch.
2. connect engine harness half of bullet connector to a clean engine ground.
3. With the key switch in the on position, the horn should sound. if the horn does not sound, the horn or wiring is
damaged.
check this and let us know what you find.

now for the RPM problem.
you need to check and see if your cables are binding up and not letting the linkage for the throttle return to idle setting.
have someone run the remote control all the way fwd, then watch the cable and linkage as they bring it back slowly all the way to reverse. see if you can find where it is binding.
let us know what you find.
 
Thanks for the suggestions coueytwo. I'll check the alarm system tomorrow. As for the RPM problem...I thought about the linkage initially and disconnected the throttle linkage at the enginge and made sure the throttle was in the idle position. No difference. I reconnected the linkage and had someone move the throttle full forward and full reverse and didn't detect a problem.
 
u need to ck--
1. carb/throttle linkage
2.timer base is moving smoothly,throttle rollers are actually THERE
3.ck fuel for WATER
4.when this occurs -ck cyl's w/temp gun for overheating
5.ck carb to carb linkages
6. throttle cable movement/connection
 
coueytwo said:
How to check your warning horn.
1. Disconnect bullet connector at temperature switch.
2. connect engine harness half of bullet connector to a clean engine ground.
3. With the key switch in the on position, the horn should sound. if the horn does not sound, the horn or wiring is
damaged.
check this and let us know what you find.
Click to expand...


This procedure is partially correct, but there is a critical piont you need to know.

The horn will NOT sound on Systems Check models UNLESS THE ENGINE IS RUNNING. 1997 is a Systems Check model.

Key on simply puts the system in what they call diagnostic mode. The tach lights will turn on for each sensor wire that is grounded (tan temp wires that couey refers to), but the horn will not sound.

This is specified in my manual on page 7-32.
 
I am learning alot from you guys. I should have asked for help with this problem two weeks ago when it started. I am going out this afternoon and try your suggestions (weather permitting).
 
Yes very true. I busted my *** trying to "fix" an non operating horn, when it was operating just as designed.

And to give much credit where credit is due, I got that bit of information from JWB....and then subsequently found it in my manual.

JWB was the source of this info.
 
Update: I tested the high temp alarm and it's working. I finally broke down and got the mechanic to make a boat call for the high idle problem. After checking compression, plugs, check for vacuum leaks, adjusting carbs, and high/low timing he came to the conclusion that the stator was bad. Hopefully, after replacing the stator next week, that will also resolve the rough running at 3000rpm like it had gone into SLOW as well. One thing from the compression test I am not sure of...What should the compression be on an 1997 J150 Ocean Runner? He was getting readings in the 80psi range across the board and said that was low. I couldn't find what the compression should be in the manual.
 
I have a 1997 J150EXEUC also. After getting back from the mechanic w new CDI ignition. He said all compression was good (if he even tested it). Would not idle. Mid and top end ok. I've changed the plugs, CDI wires, new fuel/water separator and bulb and hose, rebuilt all 6 carbs and fuel pump twice, replaced most if vacuum hoses, and emptied refilled w new gas. Still dies at idle and also when just kicking into drive. No idea what's wrong.
 
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