1995 70hp evinrude ran hot. Can I just change out the rings??

[SparkieBoat]

I got a friends E70TLEOR that ran hot, we resurfaced the head and new gasket, compression is 85, 105, 120...after cranking motor (which cranks and idles great) compression read 129, 120, 120... ran motor and it is very weak. I assume the rings need to be changed out. The pistons looked ok to me..and the cylinder walls looked good as well.
Can I just change out the piston rings??
I am trying to limit the amount of work and $$$ spent on this project as this is on a twin motor boat...and my friend will be up-powering next year. so if it is going to run into over $400-500 bucks, he will just go ahead and look at a pair of larger motors.

 

[bktheking]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

You'll need to take measurements with the appropriate micrometer ( bore gauge, t gauge etc) in the cylinder bore in several different spots to make sure it's true and compare specs in the book, just going by "look" doesn't guarantee it's going to work by throwing in a set of rings. Good to check before spending money.


And to add to it, those second comp #'s look fine BTW, something else going on with it for no power, did you verify spark and fuel?

Not sure what the first numbers are, were those before head gasket change?

 

[JustJason]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

If you have compression readings of 129-120-120 the motor should still make full power.
You have something else going on.

 

[ezeke]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

To change the rings you will need to pull and disassemble the powerhead. Rings and gasket kit plus whatever else you run into could add up quickly.

Have you done a de-carbon treatment?

 

[SparkieBoat]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

original comp #s were 120 on all, then after over heat 75, 95, 120...after head job 85, 105, 120...after craNK -UP 129, 120, 120....today after sitting for 4 days without cranking it is now 134, 129, 129...top plug is black and looks fouled out...I will check spark again...but spark was fine and plugs are new..fuel and carbs looked ok to me...and motor ran fine before over heat...I also installed new impeller and t-stat.

 

[Solittle]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

original comp #s were 120 on all, then after over heat 75, 95, 120...after head job 85, 105, 120...after craNK -UP 129, 120, 120....today after sitting for 4 days without cranking it is now 134, 129, 129...top plug is black and looks fouled out...I will check spark again...but spark was fine and plugs are new..fuel and carbs looked ok to me...and motor ran fine before over heat...I also installed new impeller and t-stat.

Those numbers look reasonable good to me. What is your rpm at WOT?

 

[SparkieBoat]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

I sprayed some deep creep into the cylinders to do a decarb...must have fouled out my #1 cylinder plug, I am pretty sure fouled out plug is my problem...new set of plugs then we will see..I thought the rings may be sticking and not working properly..but looks like compression may not be the issue...thanks , I will let you know what happens.
Sparkie

 

[bob johnson]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

what went on between the head job( and poor numbers) and the CRANK UP and good numbers???

how did that happen????

this is a motor that has the same rings still in it ...right?

is that just the compression reading after the head job...but before the motor was run for a period of time???

is that saying the head gasket didnt settle in???


with 129, 120 and 120 it seems that you dont need new rings at all.

good luck

bob

 

[kenmyfam]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

I would be looking at a bigger picture than the compression. Give it a full health check. Go from there.

 

[ezeke]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

I sprayed some deep creep into the cylinders to do a decarb...must have fouled out my #1 cylinder plug, I am pretty sure fouled out plug is my problem...new set of plugs then we will see..I thought the rings may be sticking and not working properly..but looks like compression may not be the issue...thanks , I will let you know what happens.
Sparkie

Spraying in deep creep through the spark plug holes is not a de-carbon treatment. You need to feed it into the schrader valve on the running engine and let it work before running again to do much good. It may take three or four treatments to clear all of the carbon on a two cycle engine that has not been using Carbon Guard or similar product. When done thoroughly the spark plugs should be as clean as the rest of the firing chambers.

 

[SparkieBoat]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

I sprayed the deep creep into the carbs while running. I think this is when the brand new spark plug got fouled..or while the head gasket was seating. Gasket seems to be seated now and working well. I hope a new plug is my fix.

 

[Silvertip]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

I would be investigating the cause of the overheat. Water pump, thermostat, bypass valve, block full of sand/silt, lean carburetion and perhaps some water in the fuel just to start with. Also agree that there is nothing wrong with compression.

 

[SparkieBoat]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

replaced impeller, t-stat..and cleaned and flushed motor, carbs clean and functioning properly, no water in fuel. The motor is making that hiccup noise like when your carbs are not in sync, but I checked 3 times and carb butterflies are all in sync. What else could cause it to make this noise??? Also does anyone know what the timing should be on this motor, the carb cover says 17 but they may not be the original covers.

 

[bktheking]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

Running it lean at idle will do it, have you adjusted the slow speed needles to richen up the mixture at idle?

 

[SparkieBoat]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

no I have not adjusted the carbs at all...It only started this noise after the overheat...but maybe I do need to adjust the slow speed needles, I will try it. Thanks

 

[ezeke]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

replaced impeller, t-stat..and cleaned and flushed motor, carbs clean and functioning properly, no water in fuel. The motor is making that hiccup noise like when your carbs are not in sync, but I checked 3 times and carb butterflies are all in sync. What else could cause it to make this noise??? Also does anyone know what the timing should be on this motor, the carb cover says 17 but they may not be the original covers.

Check for air leaks.

Initial low speed setting is 2 to 2-3/4 turns out from gently seated.

 

[SparkieBoat]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

they were at about 2-5/8 out from soft set. tried 1/2 turn in either direction and it made no difference. #1 plug seems to still be fouling, had a small amount of gel looking stuff on the electrode of the plug when I checked it last. Maybe plug is bad, replacing whole set again next week, when new plugs come in. Do you think maybe running hot effected one of the carb gaskets??

 

[bktheking]

Re: 1995 70hp evinrude ran hot. Can I just change out the rings??

Could be a bad plug or a carb isn't up to snuff.