mercruiser 260 hard starting after running awhile??

Happy holidays everyone. I recently did some work on my 350 small block. New intake manifolds and gasket set. plus tune up. I am having an issue with for a while now and would like to know how to fix it. Last year i was running home around 3300 rpms for about a half hour. Once I came in the canal and pulled out of gear the boat stalled. ( my shift switch is working and idle is about 700) when I tried starting it the motor was hard to crank. well I crashed into the dock and was pissed. It cooled down and then it crank right over no hesitation. Now today on land it was idleling for an hour and I shut it off and went to start it and It was doing it again. Now if I switch to both batteries it will crank it over. Plus i did a battery test with a load meter for ten seconds and both batteries had 850 cca. My ignition is around 10-11 deg its hard to read the timing tab. Any Ideas ???

Re: mercruiser 260 hard starting after running awhile??

CAPTKEV85 said:

... the motor was hard to crank.

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If by that you mean the starter would barely turn over, then you might be having a problem with heat soak. Maybe time to get your starter checked and perhaps a new solenoid. Otherwise be sure to check all of your electrical connections for looseness or corrosion.

Re: mercruiser 260 hard starting after running awhile??

Check your timing.
Make sure it's to book spec. at idle, not 1000 or 1500, idle. (600-650).

Re: mercruiser 260 hard starting after running awhile??

Don S said:

Check your timing.
Make sure it's to book spec. at idle, not 1000 or 1500, idle. (600-650).

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+1 on this. Timing should be 8? BTDC at idle (650-700 rpm).

Chris.....

From the Merc service manual...

Re: mercruiser 260 hard starting after running awhile??

Yup, I did that as a kid. We'd over advance the timing and the motor would barely crank when warm.

Re: mercruiser 260 hard starting after running awhile??

NHGuy said:

Yup, I did that as a kid. We'd over advance the timing and the motor would barely crank when warm.

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Yep, me too. Advance the timing gives that little bit more power at the top end, but as you said, the fuel charge fires too early when cranking and it actually tries to kick the engine back the wrong way...

Chris.......