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TayTay
07-09-2011, 09:49 AM
Last night went to the marina to go for an evening cruise. Crack the motor over and it sounded like the starter binder up and stopped turning over. Waited a minute then the motor started right up and idled perfectly. Decided to go ahead and take it out for a shake down run. Motor ran great no noticeable miss or anything. The problem was that it came off plane like I had a boat full of people. The boat was running about 4mph slower than normal at full throttle. At 3100rpm it was running about 27mph on the speedo it normally would be 30-31 mph. It definitely was lacking on power. Any ideas? The boat is a 1999 sc2300 with a 5.7 mercruiser 220hp. The motor has no modifications. Thanks for any suggestions
seapuppy
07-09-2011, 11:25 AM
TAYTAY..
geez...not really much to go on.....could be electrical...could be fuel....almost anything....could be a dirty bottom....cept for the hard cranking....need more data to make a recommendation..


SP
CountryME
07-09-2011, 11:51 AM
The combination of hard starting and low power would lead me to be concerned about a blown head gasket. Coolant leaking into the cylinder through the blown headgasket can lead to hydrolock and the reduced compression would cause the lower power. Get yourself a compression tester, pull all the spark plugs to prevent masking a between cylinder leak and see if you have good compression in all 8. I hope that's not the problem, but the way she acts leads me to that as the first thing to rule out.

-JP
TayTay
07-09-2011, 12:10 PM
It doesn't crank hard, just that one time it acted up on cranking. It does sit in the water all the time and we did get a 4in rain the night before. The cover was on the boat.
CountryME
07-09-2011, 12:51 PM
From your original post you stated "it sounded like the starter binder up and stopped turning over." That is a symptom of hydrolocking. The fact that is turned over fine after waiting may be because the water drained through the piston rings. Have you checked to see if the engine oil is over full or milky?

-JP
TayTay
07-10-2011, 09:40 PM
The oil looks perfect, it is full and clean no signs of water.
seapuppy
07-10-2011, 10:39 PM
water in the tank......maybe...



SP
TayTay
07-20-2011, 10:18 AM
First thanks for the ideas of what to check on the boat. After running all the diagonosis the problem was the ignition module was jumping time above 2000rpm. Put a new one on the boat runs better than ever. Happy Boating to all.