Revving outboard out of gear

thatone123

Banned
Joined
Mar 7, 2009
Messages
707
Over the years I have seen this mentioned by many that revving an outboard high, out of gear, will damage the engine. Never seen it really discussed. I have done it quite a bit with no apparent damage. Does anyone think this is a myth or factual? Talking mostly outboards under 25 hp, but also larger ones too.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Go buy a lotto ticket. I've seen both 2 and 4 stroke motors blow from over revving in neutral. In neutral I always keep the rpm down to 2500 and below.
 

G_Hipster

Petty Officer 2nd Class
Joined
Sep 24, 2016
Messages
131
it's hard on them. Engines tend to come apart when they exceed designed rpm limits, and free revving can get you there. Big difference between running it hard and abusing it.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
EDIT: Comment deleted.

More to the question, think about it. With no load, the engine can rev way higher than it was designed to withstand. Let's say it approaches 10,000 RPM. At that speed, the pistons are accelerating in one direction, coming to a total stop, and accelerating in the opposite direction, to come to a complete stop again-----over 300 times per second!!! Just imagine how much that piston weighs at the end of each stroke. And what it takes to hold it from flying off into oblivion.
 
Last edited:

SeaDooSam

Chief Petty Officer
Joined
Feb 15, 2016
Messages
575
Why would you be revving it anyway? I can't imagine a 25hp outboard actually sounds good lol. Just don't do it anymore. Not a good idea and leads to unnecessary wear and tear
 

w2much

Lieutenant
Joined
Jun 22, 2005
Messages
1,276
FR tells you like it is. But sure you can do it. Just like running a red light or stop sign.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
Hey everybody knows if your engine keeps stalling and won't idle, revving to 7000 will make it idle real smooth. Well a lot of skippers at the launch seem to think so:lol::facepalm:
 

G_Hipster

Petty Officer 2nd Class
Joined
Sep 24, 2016
Messages
131
Hey everybody knows if your engine keeps stalling and won't idle, revving to 7000 will make it idle real smooth. Well a lot of skippers at the launch seem to think so:lol::facepalm:
,

Yep,they always sound best just before they scatter. LoL
 
Last edited:

Chryslerman123

Petty Officer 3rd Class
Joined
Nov 18, 2016
Messages
87
From my experience it is fine as long as you don't over-rev it. A little throttle in neutral is fine as long as you don't go crazy and go to full throttle or it will ruin your outboard.
 

82rude

Rear Admiral
Joined
May 8, 2012
Messages
4,082
Kind of like running the motor out of water without water to the impeller ,not a wise thing to do.I still remember that guy that came on here and had a vid of the motor running in the back yard dry and he called us all aholes because we wisely pointed out that that was a bad idea.thatone123 not saying anything bad to you just remembering another no,no.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
The only time I rev high my OB's at 2500-3000 revs is when squirting power tuner through carb with OB ON and geared while flushing on muffs. Geared and at load OB runs same as in water, ungeared runs unstable, bit erratic. Just watch for the prop as it's spinning...

Happy Boating
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,046
On the trailer in gear is really still nuetral.--That prop is not doing any work !
 

interalian

Commander
Joined
Jul 23, 2009
Messages
2,105
I like running mine on muffs now and then just to annoy the neighbors - the sound resonates up and down the block. Especially good in summer when their windows are open and I can fog them with some nice rich 2smoke plus tuner fluid (mwahahaha!). A couple of little blips to richen it up and make the smoke thicker is OK, but I keep the revs lower than 2000 so I don't over-draw the garden hose.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
interalian,
If you really want to annoy the Neighbours, you need one of the 120 - 140 loopers. They have real nasty bark running on the muffs. The Combustion Chamber cleaners today have hardy any smell to them, the stuff OMC sold in the 70s would bring tears to your eyes when used. You would have loved it
 

interalian

Commander
Joined
Jul 23, 2009
Messages
2,105
I have a case of OMC cleaner that's probably of that vintage - picked it up from the shop where I worked in summer '85. The old owners were well known to have the biggest inventory of class C parts in the dealer network. The old rectangular tin with white and red label. Yes, it stinks rotten.

Oh, and unless I grenade my rebuilt xflow, they're stuck with the lower noise from that 140.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
That's the stuff!!! Probably very poisonous and bad for the environment, but boy did it soften carbon. I think it was straight Carbon Tetrachloride. Since it is so bad, I'll just have to drive the 600+ kms(round trip) to relieve you of it ;^)
 
Last edited:

thatone123

Banned
Joined
Mar 7, 2009
Messages
707
Great posts as usual. Yes, de-carbon or cleaning carb with Tune or sea foam is usually the only time I rev up. Usually not that high and never full throttle. Or when doing carb adjustments. These answers answered my questions that had the logical answers I figured were out there. In short, Ok to rev, not overdo it. BTW What are class C parts?
 
Top