1968 evinrude motor questions

[ozzgood2001]

hopefully our resident motor expert picks up on this. i have a 1968 evinrude fastwin 18 hp thats seems to run fine, but recently has been slow at spitting out water till it gets quite hot. running in a tank the last two times it has really heated up before spitting water. when it finally starts it is almost steam to start as it is so hot i can barely put my hand on the motor till the pump kicks in to cool it. i know this motor has a thermostat( i thought) . is this a warning sign of a sticking stat? should i then be worried about the impeller? when it does start pumping it pumps water well, just getting it to start. now last time at the lake i swear i looked back and it was pumping almost immediately so maybe this is a problem that is just starting i hope..give me some ideas i havent thought of!!
http://www.michigan-sportsman.com/photopost/data/550/5483downsizeboat_004.jpg

[toots]

Water pump impelers need to be changed. Take the lower unit apart. There is no thermostat. Only a few seconds of no water operation takes the life out of the neoprene impeler. I have the same moter only 67. The pump is easy to fix. There is wear plates that you may need to change. Even if the moter is not run much for it's age it needs to be fixed.

[jpollman]

I don't believe that there is a thermostat in that motor. It should pump water out through the "telltale" as soon as she fires up. I'd change that impeller NOW before you run it any more. It's not hard or expensive.

[jpollman]

Ok Oz,

I guess WE are wrong. But even if there is a thermostat I would think that you should still get a stream of water whenever the engine is running. I would think that there should be some sort of bypass or something for when the stat is closed. The pump should be pumping water whenever the motor is running. If the stat was closed where is the water gonna go ? I'm no expert on this but that's the way I see it. I'm sure Tonga will know for sure. He's probably out fishing. :)

How long have you had the motor ? Unless you know that the impeller has been changed recently, I'd change it. It's good cheap insurance.

Good luck !

John

[ozzgood2001]

just ran across this in my manual good specification sheet kinda answered my own questions so it is a thermastat. my thoughts exactly john it seems like it should "bypass" some even when its closed but it doesnt spit any water at all till it finally opens. and i do need to change the impeller i think, wasnt been done since i bought it last year and who knows how long before that. but im now worried about the thermostat
http://www.michigan-sportsman.com/photopost/data/539/5483fastwin_specifications-med.jpg

[gunrod]

I have a 5hp Evinrude and had a similar problem. It would over heat and shut down. Turns out the guy I bought it from changed the water pump and never checked the lines to and from it. They were clogged.

That's the extent of my motor knowledge. ;) I just suggest checking the lines to make sure they aren't clogged before spending money you don't have too.

[TONGA]

yes change that impeller! also check out your pickup screen,tube,tell tale,,,and yes it sounds like you have a sticky stat,,its under a little housing at the top of the head(3 bolts) so take your 3/8 wrench pop her off and have a look,,,you might even have some pieces of that old impeller up in there so like I said check out the hole system!!!
PS thats a sweet looking Rude! :D

[ozzgood2001]

what risk am i runnin if any if i take out and leave out the stat. i know a slower warmup and such but thats it i imagine other than that i see no ill effects possible?

[TONGA]

in warm weather it really wont harm anything,,but they are in there for a reason,,,if your motor dose not reach operating temp it will affect your fuel curve,,you know that's why you have to choke a cold motor,,,also if your motor dose not get up to optimum temp it will allow condensation to stay in the crankcase!!
I would recommend just replacing it,,they are pretty cheep