2021 compression test.

[chessy]

does anyone here know what compression should be on a 2021 mercury pro kicker 4 stroke  carbarator . I can't find specks on this 

 

Edited June 25, 2022 by chessy

[glen]

I don’t know. 
but it should be similar to any other engine.  
what reading are you getting?

[Fisherman]

Found this on Walleye Central, I have problems believing it though. Good results for Four-Strokes should be 180-210 PSI, and Two-Strokes should be around 110-130 PSI.

[Terry]

Yeah I think 180 is a great number for a 4stroke. But if both cylinders are the same 125 or more it would still be an ok motor 

[chessy]

19 hours ago, Terry said:

Yeah I think 180 is a great number for a 4stroke. But if both cylinders are the same 125 or more it would still be an ok motor 

the dealer is getting 115 and 121 on a 2021 with 20 hours on it ruffly ... there is a long story behind this motor... 

[Terry]

It’s not a good motor anymore 

needs work

[chessy]

7 minutes ago, Terry said:

It’s not a good motor anymore 

needs work

that's what dealer is saying but Mercury says not till below 60.... I think mercury is trying to see if it goes after warrantee ... I will no more on Monday afternoon.... ps this thing has already had 4 carbs on it ...   and from talking to people I am not even certified to hold a screw driver lol.  if carbs sucked air during break-in then that means it ran lean and can burn your pistons ??

 

[Fisherman]

Being a 4 stroke it should still have enough oil lubing it. Burning the top of the piston, entirely possible.  Unfortunately it's a Merc and we all know they make good anchors.

[chessy]

On 6/26/2022 at 10:49 AM, Terry said:

It’s not a good motor anymore 

needs work

there saying that seeing I have had 4 new carbs that it could be a carbon build up causing low compression ... does this make sense ??

 

[Terry]

Well if carbon builds up

on the rings or ring groves it can cause lower compression 

So it is possible ,but I am

no expert. Just been around long enough to have seen a few things 

[glen]

Someone needs to Pull the head and see what’s in there.  
I hope they fix it for you.  Make them. 

[GYPSY400]

Sounds like a dealer warranty problem to me.. A mercury 4 stroke should run for at least 10 years before even worrying about the compression. 

[ecmilley]

A bad breakin can cause this from ring sticking, need to.verify valve lash before continuing overtight clearances will.cause issues, especially worn