96 Evinrude 115 - Help figuring out why it melted a piston

[Joe Reeves]

Re: 96 Evinrude 115 - Help figuring out why it melted a piston

Thanks Joe. With the carburetor pictured in my post above, do you think I'd need to remove the high speed jet or is it ok if I can blow air easily through the orifice? Also, could you identify the brass screw in the upper left of the picture? I'm not sure what the purpose of this is.Cheers

I retired before that carburtor was designed BUT the brass screw in the upper left portion of the carburetor picture is a air bleed jet, no doubt a "idle" air bleed jet... I'm sure someone will jump in here confirm or correct me on this.

A high speed jet, if even clogged closed halfway... air would still pass thru it easily. Inspect it closely to avoid a possible repeat of the problem.

 

[boobie]

Re: 96 Evinrude 115 - Help figuring out why it melted a piston

Dwco, as said above this block doesn't have water deflectors.

 

[Joe Reeves]

Re: 96 Evinrude 115 - Help figuring out why it melted a piston

In agreement with Boobie pertaining to water deflectors.

 

[bob johnson]

Re: 96 Evinrude 115 - Help figuring out why it melted a piston

I have found that the BEST way to PREVENT this type of damage is to have a water temperature guage in each head!! period.... you see the temps rise.... you turn the dang thing off.!!!!!

I have three of these motors, one had a knock in one cylinder...other wise it was perfect, the other has 130 130 125 and 90 compression in the cylinders, but seems to run ok...the other I have had for 4 seasons and it is running good( except on head gets hotter than the other) I watch that head...and at idle it will run to 180 at times.... but under power it drops to 100 degrees.

telling me that water flow is the culprit most likely....I have bought 2 new thermostats yet.....but i am beting one doesnt operate well at low water pressure.... the other runs fine...

i have opened the idle setting in that head on both carbs with no change.....( i already rebuilt the carbs...)

but in the end...if i cant troubleshoot a tricky issue like this...at least i can MONITOR IT!! with temp gauges in each head......if i see the temps go past 200 degrees I shut the motor down...

and i have dont that a few times.....at wot i can get 25-28 psi in water pressure...so my water pump is fine....at idle one head runs about 140...the other is usually 160-180....

i am sure there are a few options..... the carbs have been replaced with rebuilt carbs.....but the motor has run the same with the 1995 carbs as it has with the 1996 carbs....

does anyone know of another aspect of the motor that can cause one head to run hotter than the other? the power pack? i have replaced the power pack about 2 years ago.....it didnt have an affect on the temps...( it did fix the power pack problem though)

if a passage was clogged it would seem id still have some temperature issues at wot......some at least......but both heads drop to 100 degrees at top end.....

get yourself some temp guages


bob

 

[trendsetter240]

Re: 96 Evinrude 115 - Help figuring out why it melted a piston

Thanks for the help everyone. The block is at the machine shop now. When I get it back I will clear out any of the black sealant left over and ensure all passages are clear.