yamahah 70 autolube 1996 outboard

[spikey boy]

can you please help.I did a compression test,foun top cylinder was 85lbs & the other 2 80lbs,does anyone know what they should be.Removed old gasket & found it to be cracked,fitted new gasket still not running properly
also spark plugs seem to be getting wet with fuel,could this mean it might need new piston rings?

[jb123]

check low pressure pump/s, prior to carbs...unbolt, pump ball , if leaks at ALL, replace

[spikey boy]

Hi there, do you mean fuel pump, please can you explain in a little more detail

[LakeLanierTom]

What JB means...

The fuel pump is driven by pulses of pressure inside the crankcase... If the diaphragm is damaged, it can leak fuel directly into the crankcase before the pump has a chance to send fuel to the carbs.

Don't disconnect any fuel lines, just unbolt the fuel pump from the engine crankcase. Now pump the fuel primer bulb to build up pressure and see if fuel leaks out the backside of the fuel pump (it should not).

If you use the trim to put the engine near level, but slightly tipped forward and remove the airbox from the front of the carburetors during that test, you can also find out if the carbs are flooding (bad float/needle/seat...). Any carbs leaking fuel out when you pump the fuel primer bulb will need attention.

[spikey boy]

will try thanks Tom

Hi Tom,
That is something I haven't tried yet.Will let you know how I get on.
Do you happen to know what the compression should be please?