Why do they say "she needs blowin' out"

seratime

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Dec 23, 2014
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I have talked to a fair number of people about how to run a 5.0L Mercruiser and they tell me to get it up on plane for a while every time I go out...which is frequently because running an engine at slow non-planning speeds all the time is hard on them.

I am a sailor and this is my first larger power boat with an inboard...We are retired and what I want to do is preserve the engine and use it for a long time.

Do I really need to run the engine full throttle for a brief time (plane the boat) each time I use it? All we want to do is putt around.

Thanks

Fred
 

Bondo

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I have talked to a fair number of people about how to run a 5.0L Mercruiser and they tell me to get it up on plane for a while every time I go out...which is frequently because running an engine at slow non-planning speeds all the time is hard on them.

I am a sailor and this is my first larger power boat with an inboard...We are retired and what I want to do is preserve the engine and use it for a long time.

Do I really need to run the engine full throttle for a brief time (plane the boat) each time I use it? All we want to do is putt around.

Thanks

Fred

Ayuh,.... Welcome Aboard Fred,.... Naw, Wot ain't necessary, but a nice long ride at 3/4 power, will bring everything up to temp, which Is a good thing,...

A motor that never gets fully up to Temp, will get condensation in the oil,....
Runnin' it up to temp, will steam the moisture off,....
 

JASinIL2006

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I remember people talking about spark plugs getting clogged with carbon from running at idle speeds too much... supposedly the cure was open up the engine for a while to "blow the carbon out" (which probably would burn it up, actually....). I don't know if this actually happens, but I remember hearing it when I was younger, usually in the context of a carbureted, non-fuel injected engine.
 

Scott Danforth

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welcome aboard. running the boat on plane is probably best for the engine and driveline. As Bondo indicated, it brings the temperature up and burns off the condensation, as well as helps rid the engine of any excessive build-ups. the worst thing for a motor is to simply idle along not bringing the temperature up - excessive deposits and wear occur. the best thing for a motor is to bring it up to temperature with every use, maintain it, and run it often.
 

gm280

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I have to say this really is true for most any engine. Recently my wife and I took our Blazer on a trip that lasted about three hours driving at 70mph one way. Now usually we get around 17 to 18 mpg around city/highway driving conditions. However after that six hours (for both ways) trip I'm now getting around 20 mpg. So I think we just had to bring that engine up to highway speeds to clean out everything. And I am still getting the better gas mileage yet... So there has to be something to it!
 

robert graham

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My dear old mom had a 1987 Caprice with a V8 carbed motor and twice a week she drove it about a mile to the grocery store and back and I know the choke never really opened and there was so much rich, unburned fuel and carbon in the intakes, cylinders and exhaust system that every now and then I'd take her car out on the road and run it good(blowin' it out) and the smoke would definitely boil out of the tailpipe for several miles.....I don't believe the modern fuel injected engines tend to get "loaded up" with unburned fuel like their grandpa's carbed engines but I believe any engine will be healthier and happier when it's run through the entire RPM range on a frequent basis....
 

seratime

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Dec 23, 2014
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Thanks to all you fellows...I will do the 3/4 throttle thing. I can live with that, Bondo...Now...how do I build the rpms...just go immediately to 3/4 or build them kinda slowly until it planes.
 

JoLin

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Generally, you'd smoothly push the throttle all the way forward to overcome drag and lift the boat out of the water. The bow will rise and as your speed increases, will start to come back down. As it comes down ease back on the throttle to 3/4 or so, then adjust to a comfortable speed. After doing this couple of times you'll get the hang of it and know exactly how far to pull the throttle back as you come 'over the hump' .
 

seratime

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Dec 23, 2014
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Got it... smooth to the big hole then back to 3/4...I reckon they are made to run... I have always probably been too good to my car and outboard engines. I will just Blast Off into the unknown lookin' fer my lost shaker of salt.

Thanks JoLin

Fred
 

Scott Danforth

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I usually just mash the lever forward testing the torsion strength of the throttle shaft, then back-off as she starts to climb out of the hole. its not really unknown, however please bring the lost shaker of salt, the blender is warmed and ready.
 

seratime

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Dec 23, 2014
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Thanks Scott...that's quite a well known last name...Danforth...I set two in a Bahamian rig and they held fine in gusts to 70 knots near St Michaels.
What's your coordinates...the salt is on the way :)
 

Scott Danforth

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Wish I could claim a shorter path to the founder of the anchor company, however I have a few myself.
 
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