2000 70hp johnson cuts out at 5700 rpms

[tracker14437]

2000 70hp johnson model j70plss runs great. Had a 14x17 prop with rpms running at 5200 changed to 14x15 prop rpms runs 5600 or 5700 at wot for 30 seconds and motor will break up. Have to stop shut motor off and start, will run fine at wot for 30 seconds. Is there a safty shut down set on these motors? runs forever at 5500 rpms

 

[Pro Crappie Guide]

Re: 2000 70hp johnson cuts out at 5700 rpms

Yes there is a rev limiter circuit in the power pack that will govern your top RPM.<br /><br />I don't know where it would be set at on this motor, but it sounds like you are just reving the motor too high

 

[jegervais]

Re: 2000 70hp johnson cuts out at 5700 rpms

The rev-limiter is set at (approx) 6700 rpm's. It does sound like you're bumping the limiter though. Verify your tach is set correctly (pointer switch on back should be on 6). If it's set correctly, then verify it's accuracy with a known accurate inductive pick-up shop tach. That engine should be propped to turn 5800 to 6000 rpm at WOT and it will be happy turning that all day long.<br /><br />-John

 

[tracker14437]

Re: 2000 70hp johnson cuts out at 5700 rpms

New tach and it is set at 6. Verified accuracy with pick-up shop tach . Tach is good, called dealer going to call me back 5-14-2002.<br /><br />Thankyou for your help<br />tracker14437

 

[tracker14437]

Re: 2000 70hp johnson cuts out at 5700 rpms

Dealer said new power pack, still have same problem. Now dealer said new temp sensor what do you think? help

 

[clanton]

Re: 2000 70hp johnson cuts out at 5700 rpms

Find different shop.

 

[tracker14437]

Re: 2000 70hp johnson cuts out at 5700 rpms

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[tracker14437]

Re: 2000 70hp johnson cuts out at 5700 rpms

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[clanton]

Re: 2000 70hp johnson cuts out at 5700 rpms

I would start with a compression test, and insure the VRO is pumping oil. Compression ok, and pumping primer bulb does not help. Do an engine running test of igniton sytem, with the boat in the water. You can check the temp sensor with hot water, temp probe, and meter, dealer should have these.