Compression Check 1975, 850

[1960 Starflite]

I'm back ! Told you so ! I now have the engine rewired, carbs & fuel pump rebuilt. Going to drop the lower unit to change impeller since I know it's been over 10 years of sitting (only used three times in ten years). The engine is on a stand and I want to check the compression while the lower unit is off. It has a Type III ignition system and I have not hooked any wires up to the switch box or distributor yet. Anyone see a problem cranking the engine while in this condition?

Also, anyone know the weight of this engine compared to my 1963, 650 that is on my 24ft pontoon.

Thanks, Tom on Buckeye Lake Ohio

 

[Chris1956]

Re: Compression Check 1975, 850

No, Jumper the starter solenoid, plugs out and take the compression. Weight will be 250# or so, maybe a wee less. It is one cylinder heavier than your 650.

 

[1960 Starflite]

Re: Compression Check 1975, 850

Thanks Chris. Was thinking it would be OK. My 1963 650 is also a 4 cylinder, magnito driven. Want to change out the 650 for the 850EL because I needed a long shaft. I had to cut the transom board down to get the prop to bite in the water with the 650. I'll have more questions, I'm sure.

I removed the lower unit to get to the water pump. WOW, mud dobbers built inside the pump and the impeller is toast, worst I've seen and I've changed several between the 300, 650, Pre-Alpha I/O, 888 I/O.

 

[1960 Starflite]

Re: Compression Check 1975, 850

I checked the compression, 120-125, on all four cylinders. Hooked up the wiring and fuel line, cranked a few seconds and it ran. I only let it run a few seconds (lower unit off). Rebuilt water pump and put lower unit back on. Moving on, I noticed a problem with the throttle linkage/cable. I'll start another thread on that. Told you folks I'd be back.

Thanks, Tom on Buckeye Lake