comp readings after rebuild 115 evi

[reeldutch]

i'm still a little concerned about the readings i get after i rebuild the engine.<br />the moter runs good but the comp readings differ per cylinder bank.<br /><br />125& 125 at starbord side<br />110 & 112 at portside.<br /><br />i'm almost done breaking in for 10 hrs on 25:1<br />and the comp didn't change much.<br /><br />i had the heads resurfaced is that the cause of it?<br />will this be a problem.<br />im 100% shore the rings are all in great shape and the cylinders to.<br /><br />thanks reeldutch

 

[GatorMike]

Re: comp readings after rebuild 115 evi

I feel just a little better about my numbers, Just finished my rebuild a week or so ago and got 120, 120, 120 and 125 after 1 hr of breakin. The only thing that worries me is I saw someone in one of your previous posts say compression usualy goes up during breakin. Dang if that happens I may have to write Mercury across my Johnson.

 

[outboardkiwi]

Re: comp readings after rebuild 115 evi

Hi reeldutch<br /><br />I rebuilt my 1989 Johnson 90 V4 last year and prior to rebuilt the port bank was always 10psi lower than the starboard bank. I rechecked the compression the other day after approx 5hrs running and got:<br /><br />Port 125, 125<br />Starboard 135, 135<br /><br />I used a screw in dial test indicator in each spark plug hole to measure the piston height relative to the head and noticed the starboard pistons were coming up higher or closer to the head by approx .015 - .020” than the port bank, whether this would explain 10psi difference between banks I’m not sure but maybe worth having a look at on your engine.<br /><br />Also do you the know what your compression was like prior to rebuild

 

[reeldutch]

Re: comp readings after rebuild 115 evi

no i do not have any compresionreadings prior to the rebuild.<br /><br />what i just want to know is because i differ 15 lbs from highest to the lowest cylinder,<br />if this will cause any problems???

 

[Dhadley]

Re: comp readings after rebuild 115 evi

What year 115? Are the heads a matching set? How far was each one milled?

 

[Hotrods]

Re: comp readings after rebuild 115 evi

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[Chesapeake Explorer]

Re: comp readings after rebuild 115 evi

When My 88 90 hp Evinrude was brand new I had 120 lbs compression on all 4 and then it went down on the starboard bank to 115. So See how it goes . 120-125 is like brand new. 115 is still like a new motor.

 

[walleyehed]

Re: comp readings after rebuild 115 evi

Reeldutch, P/N's for the heads are cast right into them...can you give us those numbers?????

 

[reeldutch]

Re: comp readings after rebuild 115 evi

the heads are matching sets.<br />the numbers are 326 504<br /> 326 505<br /><br />this is from a 1990 V4 115 hp bubbleback.<br /><br />i dont know how much the machiner took from each head.<br />What can i do or figure out.<br /><br />The moter runs fine but i just would like to see it more even.<br /><br />thanks for your help<br /><br />reeldutch

 

[Hotrods]

Re: comp readings after rebuild 115 evi

Mine cold .....today<br /><br />115 115 Starb<br />105 105 port<br /><br />Im in the 8th hour of break in<br /><br />prior to rebuild<br /><br />75,120<br />120,120<br /><br />So what does this mean?

 

[reeldutch]

Re: comp readings after rebuild 115 evi

sound like the same situation to me.<br />i dont know what it means all i know is that<br />the pistons and rings are all in great shape and that the heads were resurfaced.<br />the motor runs great.<br />is there a explanation???<br />the two lower cylinders where bored .20 over and the top ones where honed.

 

[Hotrods]

Re: comp readings after rebuild 115 evi

Inconsistency in an high hour motor would show problems, as ours did. Im thinking in a rebuilt motor it may show nothing more than a few thousands in the difference of tolerances per cylinder/rings/pistons/heads and getting all this to level out would take more than 8 hours of running if it will at all. <br /> Boy!! that sounds good to me but what do the pro's think? I don’t think we have a problem at all. Took her out yesterday 4-7' swells/chop in the ocean and she handled it well.. It was a hell of a ride...mainly large swells, motor powered great keeping me on them...<br /><br />IM HAPPY!!!