mercury 1976 850el

[07hotrodchevy]

I have a 1976 mercury 85 hp 850el it runs great out of water in gear or out of gear as soon as i put it in water and engage the gears to forward or reverse it shuts down it will fire right up in neutral put it in gear it shuts down every time it was hooked up to a dana machine and it worked just fine it just will not run in water i have had the carbs rebuilt the fuel pump a new stater does any one have any idea why would this happen?? my boat doctor has worked on out boats for 30 years and is stumped its been a year now and no ideas in sight please help. Thank you,
KM

 

[racerone]

When on a hose and " in gear " there is still no load on the motor !-In gear is still the same as nuetral.----Try opening the low speed jets 1/4 turn at a time and see what happens.----Compression test results are ?---------Reed valves checked ? ---lower crankshaft seals checked ?

 

[07hotrodchevy]

When on a hose and " in gear " there is still no load on the motor !-In gear is still the same as nuetral.----Try opening the low speed jets 1/4 turn at a time and see what happens.----Compression test results are ?---------Reed valves checked ? ---lower crankshaft seals checked ?

Thank you yes compression test were great the other test i have no idea but i will go Monday to find out and or get him to check those