Honda 135 temp.alarm problem

[bcarli]

Hi
I have a honda 135 on our boat with 2200 hours. A few weeks ago after having the boat serviced ( I don't think the alarm started going off before the service but I can't be sure) the temp alarm suddenly goes off when I back it down to neutral after running the boat for an hour or so. I have a honda tach gauge so I know it is the temp alarm not oil pressure. The alarm does not always go off just occasionally... I had new thermostats installed in the first service. I took the boat to a honda dealer here in the pacific northwest and after putting the engine on their computer installed a new impeller. They charged me $600 for the haul out and impeller...seems very expense to me...I also have a small oil leak and I have no idea if that is part of the problem...Anyway after the new impeller, new thermostats the engine alarm still goes off on occasion. The new impeller had no effect...So I'm at a complete loss.Could it be a bad sensor????
Any ideas? I'll be watching for any response...thank you
bill
friday harbor, wa

 

[chawk_man]

I would pull and test the thermostats as a first step. Your owners manual should provide the procedure for doing that. Also, if I recall correctly, that engine has two t-stats that are different from each other. It may be possible that they were put in wrong, or have the wrong t-stats, so that is another reason to pull them and check. A third reason to pull them is to check for excessive corrosion around the t-stat seat area.

If you want to save money on maintenance, invest in the official Helm shop manual for that engine. Do not waste your money on the aftermarket shop manuals - too many errors and omissions.

 

[hondadude]

CHawk is right. The rear thermostat will have two raised notches on it and the one more forward will have three notches on it.

Mike