Thermostat EV 90HP '85

[mutron77]

Hello<br /><br />I heard it was a bear changing one of these. Has anyone done it? Mechanic said during tune up that heads were too cool to the touch indicating an open thermo. He said to take it out and run it around the lake and see if it frees up. He said if your hand doesn't start getting uncomfortably hot after several seconds touching the head, then the stat is stuck open and engine may load up at lower speeds.<br />He said it is a 2 hour job so I should make sure that it needs to be changed before going through the trouble.<br /><br />thanks<br /><br />H90

 

[rodbolt]

Re: Thermostat EV 90HP '85

hello<br /> well if its so old its stuck the bolts may be stuck as well. this goes back to what I said about maint. do it.<br /> do it often.<br /> pay me now or pay me later. dont whine at later.<br />if the bolts are free I can do that in 45 min. I can do a bubble back in 2-2.5 hrs. if I have to cut the housing now that flat back takes 3-4 hours and the bubble back goes to 4-5. if the bolts break and have to be drilled the attempt to remove the powerhead starts. now we may be at 9 to 20 hours.looks good on my paycheck but its tough on your wallet. that is why I say do it. do it yearly or at least every other year. or just run it till it dies and tell everyone what a bum motor that one was and go buy it new.<br /> good luck and keep posting<br />PS I dont mean to sound like I am busting chops but preventative maint is just that. follow the service guides. change things before you actually need them. me if I know that t-stat is sticking I would fix it first. if it sticks shut and the sensor or horn picks that time to fail,on jonny/rudes its common, then you will be buying pistons with that t-stat. the nice thing about it is the t-stats are easy to get to with the power head off

 

[OBJ]

Re: Thermostat EV 90HP '85

Yeah.....what rodbolt said.....<br /><br />The t-stats on these V4's are a pain to get to but can be done without pulling the head. During reassembly, clean the bolts real good and apply a coat of gasket sealing compound to them. This will help prevent them from corroding in. Make them easier to come out the next time.

 

[mutron77]

Re: Thermostat EV 90HP '85

I think I'll go get me a stat, thanks for the advice. You say it is common for the OH hour to go fail? Is it usually the horn or the sensor? At any rate I haven't been able to get mine to test out, so I'm shinking of pulling tha console and checking the horn and wires.<br />H90

 

[reeldutch]

Re: Thermostat EV 90HP '85

i did my tstats resently for the first time.<br />i have a bubbleback and i did drill 3 holes in the lower engine cover.<br />i had to do it twice because with putting the tstats back in something went wrong with the left tstat.<br />so it is defenetly a pain but after a few times it will go easyer and it is not so hard.<br />i'm going to do this every season thats why i drilled the holes.<br />a mechanic will charge me 400 dollars to lift the powerhead and chance the tstats.<br />it is better i agree but very costly.<br /><br />reeldutch

 

[Solittle]

Re: Thermostat EV 90HP '85

H90- I am a driveway wrench (not a pro by any means) & did my two 1987 bubbleback 1.6L SeaDrives last year. I did not pull the powerheads nor did I drill the lower pan. I did lower the pan on one motor though. I used a 7/16" box wrench and a 1/4" drive socket with an extra long extension & universal to take out & install the three bolts. When ready to reinstall I used rubber bands to hold the parts together until I had the bolts barely started then cut the rubber bands.<br /><br />The OMC service and parts manual were a big help. I also got some help here from the guys on something I did not understand. It may help to call for an extra set of hands from a neighbor in the reassembly. You can pay for these manuals by what you save in this job alone.