Logo
FULL SITE MENU

Alarm & Tach problems 2012 90 HP Honda

M

Mako5

New member
Hoping someone can shed some light on this problem. 2012 Honda 90 HP Fuel injected. Getting high water temp alarm but getting good water flow and water is very cool. In addition tach is going crazy reading all kinda of weird rpm at idle or faster speeds. Mechanic checked thermostat and changed water pump. Computer when hooked to engine showed no codes for overheat. Anyone ever seen this weird problem before. Thanks for any advice.
 
You may have two separate issues.

Is your overheat light coming on with the alarm?
Were you getting a solid audible alarm?
Was the oil light on at the time?

Did the mechanic see the problem occur and use Dr. H to see if the ECU was seeing normal readings from the sensors?

If the ECU is indicating it is seeing normal outputs from the sensors, then the issue could be somewhere on the engine wiring harness or the wiring harness going to the helm.

If the overheat light is not on but the oil light is....indicating all is normal...and you have a solid alarm.....you could have a low battery. That could cause an alarm without operating any lights. It usually occurs just at startup when there was a lot of draw on the battery.

In those kinds of problems, you have to get it to fail to find it, unless there is something very obvious or you get very lucky.

As for the tachometer....

Many times the contacts on the selector switch on the back of the tach get corroded or dirty. Most tachs have a rotating selector switch to allow it to work with different engines. Check to see where it is currently positioned, then take a screwdriver and rotate the switch back and forth vigorously a few times ( to clean the contacts). Be sure to put the switch back into the current position when finished. '

In about 80% of the cases of jumpy tachs, that fixes the problem.

Mike
 
Thanks for responding. Yes the light and alarm are coming on at the same time. (Brand new battery) Yes to the solid alarm. No oil light on. Don't know about the readings on computer. The only thing he said was that it was not showing where there were any cases of overheating. I think I failed to mention that when alarm and light went off I pulled throttle back to neutral and let idle after about 15 to 20 seconds engine shut down. Restarted engine right away and now alarm. (Mech wasn't present for this). I know I am probably not giving enough information. Will try the tach switch. Thank you both for your responses.
 
More questions and possibilities....

You said that the oil light was not on. That could also be a problem and cause an audible alarm. The light should be on, if the engine is running and the oil pressure is good.

Does the alarm and light come on as soon as you start the engine....or does the engine have to run for a few minutes before it comes on?

If the alarm comes on right away....then there could be a short to ground somewhere in your wiring harness.

It sounds like your mechanic left the job too soon....there is a lot more testing that he should have done.

Mike
 
Mike sorry for taking so long to reply. Had to leave FL where my boat is unexpectedly so it will be about a week or so before I can get back. The oil light is not on that I know of. The high temp ? alarm doesn't come on until you run the engine for 10 to 20 minutes at elevated rpms. Last trip out ran boat at about 2000 rpms (if tach was right) for about an hour trolling and never got an alarm. Ran for about 10 minutes at elevated rpms (but tach was going crazy) but I was up on plane so I know they were up and them the alarm. I think you are right about mechanic needs to do a little more checking. Being a non mech I just had to put myself in his hands. Thank you for taking time to respond and trying to help.
 
I just thought of one more thing to ask him....

You said he checked the thermostat....did he check both thermostats? There is one in the head and one in the block. The one in the block is hidden behind the ECU and associated parts....it is not so easy to get to.

Mike
 
Just wanted to say thank you for your help. Looks like I am back to square one. Mech checked thermostats both Ok. (I know the tach is bad) Ran boat high speed today for over an hour with no alarms at all. Oh yes the green oil light that you asked about was on the whole time. Had his computer hooked while we were running, nothing. I guess I just gonna have to wait until it does it's thing all the time. Anyway I just wanted to say thanks for trying to help.
 
Back
Top