Compression test—OOPS!

Hi all

(I have also posted this on iboats.com >>> Compression test—OOPS! - iboats Boating Forums)

I was doing a comp test on my Yamaha 50HP 4 stroke-
Yamaha F50T
1994 or 1995



And---- the gauge’s valve stem got sucked into number one cylinder and then started to blow back out in little pieces!

I bought a new comp gauge and yup-- Cyl one reads way low—

Cyl1: 25 PSI
Cyl2: 175
Cyl3: 180
Cyl4: 175

I have never opened up an engine before. I have the pdf version of Lit18616FT50 which I purchased on the net last week. I have lots of time.



---------
I have since removed the head-- looks OK.

Cyl 1 is full of ground up valve stem.

I am trying o get piston1 out.

Please--- do I have to remove the entire powerhead to get the crankcase cover off, so as to get that piston out.

Thanks a lot-- Rick in Anchorage.

[boats.net]

Yes to remove the piston the powerhead would have to be removed.

Thanks

Thank you.

Everything points to the cyl being OK. I am reassembling now.

Rick