 2nd opinion yam 115 overheat
1989 model 115 yamaha. motor seems to run fine until 4000 rpm or higher,alarm goes off and cuts engine to reduced rpm. Ck heads with temp gun 135 to 145 degees.let engine continue to idle and cool and when alarm goes off cotinues to run unless you go over 4000 rpm. did a search on this site and cked for loose connections ground etc. no luck take it to a local yam dealer(fresh water) and he want's to overhaul.since the compression cks above 125 on all cylinders I give him $70 and say not yet. Mech at my coast home says let him have a look. he thinks motor is in really good shape and does not need overhaul,so goes to looking for overheat cause. the thermostats have been replaced,water pump replaced, poppit cleaned and inspected.themoswitches cked ,can't find anything wrong with engine. Launches boat and overheats above 4000
Or more specifically the alrm goes off.pulls heads of and ck for water restrictions, all clean.replaces new water pump said that the other one was not oem, I reminded him that I bought the waterpump from him 3 months prior.alarms again. He now suggest the next thing to do is to pull powerhead and look for
"airleaks into or from the exhaust.?? Estimate for that another $387, I asked him to hold off and let me think about this as he alreadt has probably 700 -800 in charges to date.
I really am at a critical point here as the motor of that age is probably only worth a couple of thousand at best . I also believe that he is looking in the wrong direction as I don't believe the motor is overheating 135 -145 degrees and that the problem lies with the temp alarm in some way. Any suggestions would be greatly appreciated, sorry this is so long
Thanks
marc | 
