Mariner 150 middle bore compression low parts needed

[Samjackson]

Done a compression test on my 2.5 v6 mariner 150hp
the two top bores are 125psi
The middle bores are port 60 psi and starboard at 5psi
The bottom bores sit at 125 the pair
Need to know all parts and possible prices for them
Also what I would need to do
I have worked on smaller engines but never a v6 rebuild.
Any help and advice is appreciated on how this could have happened and how to fix the problems
Thanks

[adykitcher]

I dont think anyone could price with out seeing the damage first as it could easily be a right off. I would start by buying a Manual!

[still no worries]

Just take the heads off, you should be able to see how bad it is then, anyone looking at it for you will do that first. Also it sounds like a problem with the middle carb has caused this, make sure you sort that before you run it again.

[Frenchbruno]

Following your numbers , better to check reeds, they're probably made with stainless steel, and I supect you've some broken ones......
You can use also buy a little camera borescope.
2 5 10M 8mm 2EN1 USB Endoscope Borescope Caméra Inspection Etanche PR Android PC | eBay

very useful, here I've added a picture of reeds inspection made one week ago
This avoid you to remove heads, air plenum, and save time, you can't see everythings as in a nice day light, but for the price a useful tool.
for cylinder bore inspection too, you have a little angle mirror.
better to use this on a computeur as the leds put down the cell phone battery very fast, also, you should need to download a specific software to use the borescope, nothing difficult.

You can also use a leak down tester, not so expensive too, and useful also.
Cylinder Leak Down Tester Automotive Diagnostic Tool Wholesale Auto Shop Tools | eBay
Good luck.

[Sam1cats]

Hi if you want me to look at it I'm in Bournemouth If you bring it to me For 50 quid I Wheel Remove the cylinder heads and tell you what's wrong I also have all the facilities to get it rebuilt And hundreds of parts in stock second hand If you want to do on a budget Give me a call 07886669198 Keith