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Posting a reply to: Re: Need advice for problem w/150HP Johnson

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[QUOTE]MACK - 7/3/2007  8:16 AM

I just went through something similar with my '97 90 Johnson 2-stroke oil injected motor.

I kept having the alarm sounding as well, only at WOT however. I'd shut it down and then restart it and it'd be fine.

I had just had the thermostats and the impeller changed with an engine tune-up overhaul at that time.

What we found to be the issue..happened to be two things at once...at least that what the marina "told" me. I'm still a little suspect of it all myself..but..it's water under the bridge now.

My boat uses the Faria guages and my tach has the system check built into it. Well..the tach was supposedly going bad and was sending/receiving false information at times, which would sound the alarm. Then...supposedly..in addition to that...when my specific '97 90 hp Johnson was coming off of the factory line, OMC was still using some internal parts on those new '97s (back then) from their '96 line. Supposedly...there was a thermostat change from the '96s to the '97s with a different operating temp. The marina kept putting '97 thermostats in the motor and it'd cause this problem at WOT throttle..the motor thinking it's overheating because the thermostats were not opening up'. They ran the heat gun on the motor with the cowling off and found no overheating issues. So...then they magically found out this tid-bit of info of my specific motor needing thermostats from the '96 line. They swapped those in there....supposedly...and all is fine now with those supposed '96 thermostats and the new tach. Now...like I said...it all sounds suspect and like a story to me to cover their own arses...but...at least my motor and my boat runs flawless now, like a dream. Only thing I'm bumming now is that the tach the marina replaced into my dash is not a Faria brand and does not match at all. Kind of an eyesore to see nice white on black gauges all across the dashboard..then there's the screaming, bright orange on black gauge of another brand.

I JUST got on-line last night on ebay to check for another Faria systems check OMC tach and found one. So...I may pop for it and have it put in so it matches once again..then  just hold on to the goofy looking one for that just-in-case scenario down the road again...

Not saying your problem is like mine...but..something to consider.

Having said that you put the heat gun on yours and you're seeing one bank running hot...certainly could mean a bad thermostat...or..one that's got some small rocks/gunk stuck in it that won't allow it to open/close correctly. At times..when running in shallow water...sucking a lot of junk up off of the bottom of the lake through the coolant intake gets caught up in there. Thermostats aren't expensive and it's not a bad deal to replace them on a regular basis though.

If you're in there and haven't done the impeller in a while...go ahead and do that too just for good measure.[/QUOTE]

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MACK

Posted 7/3/2007 8:16 AM (#263491 - in reply to #263282)
Subject: Re: Need advice for problem w/150HP Johnson

Posts: 1086

I just went through something similar with my '97 90 Johnson 2-stroke oil injected motor.

I kept having the alarm sounding as well, only at WOT however. I'd shut it down and then restart it and it'd be fine.

I had just had the thermostats and the impeller changed with an engine tune-up overhaul at that time.

What we found to be the issue..happened to be two things at once...at least that what the marina "told" me. I'm still a little suspect of it all myself..but..it's water under the bridge now.

My boat uses the Faria guages and my tach has the system check built into it. Well..the tach was supposedly going bad and was sending/receiving false information at times, which would sound the alarm. Then...supposedly..in addition to that...when my specific '97 90 hp Johnson was coming off of the factory line, OMC was still using some internal parts on those new '97s (back then) from their '96 line. Supposedly...there was a thermostat change from the '96s to the '97s with a different operating temp. The marina kept putting '97 thermostats in the motor and it'd cause this problem at WOT throttle..the motor thinking it's overheating because the thermostats were not opening up'. They ran the heat gun on the motor with the cowling off and found no overheating issues. So...then they magically found out this tid-bit of info of my specific motor needing thermostats from the '96 line. They swapped those in there....supposedly...and all is fine now with those supposed '96 thermostats and the new tach. Now...like I said...it all sounds suspect and like a story to me to cover their own arses...but...at least my motor and my boat runs flawless now, like a dream. Only thing I'm bumming now is that the tach the marina replaced into my dash is not a Faria brand and does not match at all. Kind of an eyesore to see nice white on black gauges all across the dashboard..then there's the screaming, bright orange on black gauge of another brand.

I JUST got on-line last night on ebay to check for another Faria systems check OMC tach and found one. So...I may pop for it and have it put in so it matches once again..then just hold on to the goofy looking one for that just-in-case scenario down the road again...

Not saying your problem is like mine...but..something to consider.

Having said that you put the heat gun on yours and you're seeing one bank running hot...certainly could mean a bad thermostat...or..one that's got some small rocks/gunk stuck in it that won't allow it to open/close correctly. At times..when running in shallow water...sucking a lot of junk up off of the bottom of the lake through the coolant intake gets caught up in there. Thermostats aren't expensive and it's not a bad deal to replace them on a regular basis though.

If you're in there and haven't done the impeller in a while...go ahead and do that too just for good measure.