Force 90 Temp Alarm

[barron]

Last weekend while at low idle the temp alarm went off (continuous tone?) motor was very hot. I shut it down right away, there was not water circulating and there was quite a bit of smoke from the water outlet. What do you all think ? the motor was running when I shut it down, the alarm sounded for about30 to 45 sec before being shut down. At a minimum I would expect a new head gasket along with impellar - but in your experience can I expect a more radical repair ? thanks for your responses...

 

[lonewolf5347]

Re: Force 90 Temp Alarm

THE FIST THING I WOULD DO IS TO TAKE A COMPRESSION TEST ON THE CYLINDERS.DEPENDING WHAT YOUR READING ARE WILL TELL YOU IF YOU HAD ENGING DAMAGE.THEN THE NEXT THING WOULD BE TO INSTALL A NEW IMPELLER IN THE LOWER UNIT. NOT THAT HARD .the other thing i would do is to install a temp. gauge on that outboard.the force engines have no place to install a sending unit.so what i did on my engine was to install a surface temp . gauage ,that will read surface temp. it works great.

 

[oldboat1]

Re: Force 90 Temp Alarm

salmon2 -- See Frank's analysis/response in the thread "overheating problems?". There is a range of symptoms....<br /><br />You probably shut her down quickly enough. Smoke isn't the best of signs, of course, but it's hard to tell what is OK in the way of smoke and steam from 2-cycle outboards. You need to correct the water circulation problem, and that should mean a new impeller. I think Lonewolf might be telling you to see if the engine is damaged before spending a lot of time or money on the lower unit, and that is good advice. If you are handy, though, you can change the impeller yourself for the cost of parts. When you get the impeller out, you will likely be able to see if it's the cause (broken vanes -- may find it in pieces). It's better to replace it anyway if you get that far, but the condition of the old one will give you a pretty clear idea whether you will need to look further to solve the cooling problem. <br /><br />If there is no visible damage around the head (scorching or paint bubbling), you are probably OK -- and you might be OK even with some visible signs. I don't think a new head gasket is necessarily needed. Chances are, you will fire it up with the new impeller and everything will work fine.

 

[Franki]

Re: Force 90 Temp Alarm

do a search of the archives of this list if you are wondering how to add an external temp sender.. there are a heap of posts.. I did it recently to my old OMC... works great..<br />Schematic and others added alot of useful tips and suggestions.<br /><br />If the alarm went off at low idle, and you turned it right off.. how come the alarm sounded for 35+ seconds??? are you saying that it kept going for some time after the ignition was turned off? or are you saying it took you 35 seconds to kill the engine? (why so long??)<br /><br />if it kept sounding for 30 odd seconds after it was turned off,,(are they supposed to do that?) then you only had it running for a few seconds after the temp alarm went off.. and at low idle and the fact that the alarms are supposed to go off long before damaging temps, then you are probably ok.. if you are not sure, then do the test..<br /><br />I have cooked a couple of motors in the past that had faulty alarms.. to the point where the paint was crackling, and once cooled off, they ran fine. I probably lost some compression due to loss of ring tension, but nothing noticable..<br /><br />(In fact, I cooked my old Lark40 evinrude several times due to a lower unit problem, and it still runs great and seems to have alot of compression..)<br /><br />Its only really really bad when things start wielding together in the bores.. you might be ok..<br /><br />a few seconds of running after the alarm went off at low idle sounds like its not gonna be that bad..<br /><br />But do a compression check as suggested if you are at all worried about it. and check your thermostat as well as the impeller.<br /><br />rgds<br /><br />Frank

 

[daschtick]

Re: Force 90 Temp Alarm

My Force 120 has done that to me once or twice also, even when it was brand new. It is not an impeller problem - it is a Force quirk. It usually happened after running hard for several minutes, then quickly brought to an idle for quite some time while still in gear. Because the temperature sensor is on the very top of the block, and the engine is really warm, and you've suddenly reduced the cooling circulation to an absolute minimum, it may not be enough to cool the motor from the previous run.<br /><br />I usually try to reduce my speed somewhat gradually, and this no longer has happened. Otherwise, I try to keep my idle above 1000+ RPM after such runs to keep the cooling system working properly. Force cooling systems don't work quite as well as other makes at low idle speeds, and this is evident by the little or no water exiting from the pee hole during low RPM operation. As long as the RPM is high enough usually 1000+), you will see a steady stream, and have adequate cooling.<br /><br />-Nick

 

[oldboat1]

Re: Force 90 Temp Alarm

interesting. Like the office computer guy might say, "It's a feature."<br /><br />I had a mid-'70s Chrysler 105 with similar symptoms, never really diagnosed. The mechanic who worked on it (after I returned it the second or third time), finally decided that it was a problem with one of the wrist pins (scored the cylinder wall), and the defect was somehow causing the motor to run hot. But whatever he did (I know I didn't have him replace or repair pistons), the motor ran OK after that -- no buzzer, which he may just have disconnected. It isn't clear the motor really was ever running hot, now that I think back, as all I was responding to was the warning buzzer.<br /><br />So maybe it's a feature that Force inherited from Chrysler.

 

[barron]

Re: Force 90 Temp Alarm

Thanks everyone for their help. Franki, what happened was I ran up river for 20 min or so and then throttled down to just off idle. I had the stereo on so when I first heard the alarm (I am pretty sure I heard it when it fist went off) I first shut off the stereo - the alarm kept sounding and I didn't recognize what it was so I cycled all of my electical switches to see what the effect was, I got a slight change of pitch when I cycled the bilge pump, thats what brought me to the stern where I saw the outboard smoking pretty good, thats when I turned off the motor. The alarm stopped once the key was turned off. Thanks again. I will do the compression check and go from there.

 

[Franki]

Re: Force 90 Temp Alarm

When it overheated and you shut it off.. did you take the cowling off and take a look?<br /><br />If so, how hot was it? was it crackling? <br />does the paint on the head and block look darker around the heads?<br /><br />even when my lark40 was cooking,, the only place that was smoking was the paintwork on the heads and block.. there was nothing extra coming out the back that I noticed.. If may have been mostly steam, in which case its a good thing as it means there must have been some water in there.. so again, you might be lucky.<br /><br />I can't imagine why there would be unless there was some serious stuff going on in your bores...<br /><br />A compression test is really the way to go here..<br />if they are still close together.. then maybe you got lucky.. <br />I recently came to the conclusion that I wouldn't here the alarm buzzer on my OMC if it overheated..so I added a temp guage.. and replaced the buzzer in the controller with a relay and hooked the relay up to a full size car horn and put it right behind the dashboard..<br />This thing is loud.. I tested it and almost deafened me.. I won't miss it, stereo or not.. <br /><br /><br />Still, look at it this way.. if you had been WOT when it happened, your motor would very likely be in a card board box in your garage.. or spread all over the water or being used as a mooring..<br /><br />rgds<br /><br />Frank

 

[JoeCrow]

Re: Force 90 Temp Alarm

I have a Force 125 that's been driving me nuts for weeks
The alarm goes off at WOT, cut back to 1/2 and it silences, idles fine WOT for more than a few minutes and the alarm goes off
I replaced the impeller, impeller housing, bushing, thermostat, thermo spring and even repropped the boat to lower the RPM
ALARM STILL SOUNDS after a few minutes at WOT
After reading every manual I could find, I came across an obscure reference in Seloc's Force Outboards 84-99 Repair Manual #1100
On page 6-10 it says:
"there were 3 different sending units, red, white and black all set for different temperatures. They have all been replaced with new higher temperature design and the manufacturer recommends that all units be replaced with the new design"
That's were I am now and hopefully it will end my headache
Someone also mentioned that this was a recall at one time