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Old 03 May 2014, 02:20   #1
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I have a 1998 Honda BF8A. When running it at full throttle the other day i suddenly experience a loss of power and when i turned around white smoke was coming from the exhaust holes. The engine seems to be pumping plenty of water and runs fine at lower speeds. Spark plugs and fuel filter have recently been changed. Any help would be much appreciated. Thanks EofZ
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Old 03 May 2014, 02:51   #2
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If this was a car I'd say the head gasket has gone. Someone will be along soon to correct or confirm


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Old 03 May 2014, 03:04   #3
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Could be that white smoke was steam. When was the impeller last changed? Id inspect that first to check there isn't a broken blade. I'd also check the thermostat. Remove it and test it in boiling water to see it opens. You may need a new gasket to reinstall.

Take the cowl off the outboard and check the head gasket for any corrosion or signs of gases when it's running on muffs. Finally, change the fuel, the loss of power could be water in the tank.
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Old 03 May 2014, 03:23   #4
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New impellor was put in last year and it has hardly been run

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Old 03 May 2014, 04:28   #5
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Quote:
Originally Posted by earlofzetland View Post
New impellor was put in last year and it has hardly been run

EofZ
Impellers are good for every other year, so assuming that's fine, then check the other things I indicated. While you're at it, check the oil level and that the oil isn't contaminated.
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Old 03 May 2014, 06:01   #6
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Cooling system check and then head gasket, outside chance of a bottom crank seal.

If you have had water entering the combustion chamber, it can seize the engine, so some oil down the bores would be advisable until you have time to fix. WD 40 down the air intakes to protect the crank, do this with engine running.
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Old 04 May 2014, 16:06   #7
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Cheers for the advise so far guys. To help my understanding of the possible cause could someone explain why a dodgy thermostat would cause a loss of power?
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Old 04 May 2014, 16:16   #8
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Dodgy thermostat could cause an engine to overheat, if it overheats too much it can cause the head gasket to fail or the engine to tighten up.

Both symptoms can cause loss of power.
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Old 04 May 2014, 16:46   #9
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Thanks. Wouldn't a steady stream of cool water from the telltale indicate the thermostat is working ok?
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Old 04 May 2014, 16:55   #10
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White Smoke and Power Loss from Outboard

No, its not a given. Tell tales can come off before going around cooling jacket.
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