Yanmar 3GM hard starting after injector service

[Rappey]

Before starting try pumping the fuel pump by hand (might require lots of pumps) and then see if its easier to start.

Has this been tried? A friend rebuilt his yanmar. Great compression but really hard to cold start. He tried virtually everything but no joy.
Yesterday he told me he pumped the fuel primer before cold starting and it fired straight up.

 

[Slowboat35]

My 60 year old bmc measures within 10 psi on all 4 cylinders ! I'm down to 260. It should be 340 for me. Saving grace is that it has glow plugs so still starts.
30 years ago i could do 7.5knts, now only 6.5knts.

For a start I clearly said "is seldom lost equally" - the operative word being "seldom"...
Secondly regardless of your quoted numbers "all the advice I have had on compression is that absolute numbers are a completely unreliable guide to compression health as there are so many variables in the (uncalibrated) measuring process."

 

[vas]

Didn't even know you had glow plugs. If you have, that is a must check first item on relay, wiring and plugs.

no glow plugs on GM series

 

[vas]

Had all sorts of issues with my 2GMF on a 8kW generator onboard.
Turned out (after an almost needless full engine rebuilt) that it was a combo of things all related to fueling.
Scrapped the awful lift pump that was leaking air in the circuit (replaced with a 50euro el fuel pump that I fire a few secs before cranking), rebuilt/replaced various bits in the primary yanmar filter and now it starts (OK not on the button when below 10C) reasonably well at 1/2 accel

 

[IanCC]

Has this been tried? A friend rebuilt his yanmar. Great compression but really hard to cold start. He tried virtually everything but no joy.
Yesterday he told me he pumped the fuel primer before cold starting and it fired straight up.

Just decompress and spin engine for 5 seconds or so. That will bring fuel up to pressure. If it works you definitely have an air leak.