Running with low speed can damage a 2 stroke engine ?

delfinasul

Seaman
Joined
Feb 15, 2007
Messages
69
Generaly speaking i run my engine (suzuki dt40 with oil injection) close to 5000 rpm's when i'm in deep waters but i'm wondering if i run for 10-15 minutes or more at low speed , let say about 2000 rpm's (when i'm in places with low water, beaches, etc) if this can damage my engine. What do you think?

A.Cosmin
 

Rudy Brown

Petty Officer 1st Class
Joined
Apr 3, 2005
Messages
289
Re: Running with low speed can damage a 2 stroke engine ?

You'll be ok at low speed. My evinrude will idle all day no problems.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,778
Re: Running with low speed can damage a 2 stroke engine ?

If you are concerned about carbon buildup then keep Sea Foam in your gas and don't worry about it......

However, if your boat is slightly under planing speed (big wake) when you do this you could be experiencing high combustion temps as you engine is under maximum stress..... which is not good. Dhadley can explain that for you.

If you are going slow enough that water is still in contact with the rear of the transom then go for it.

My 2c.

Mark
 

delfinasul

Seaman
Joined
Feb 15, 2007
Messages
69
Re: Running with low speed can damage a 2 stroke engine ?

Yes, that i want to say, very slow , usualy i run in this way when i try to find a good place for fishing running near or above submerged trees because i don't want to broke my prop or scarring the fishes .

A.Cosmin
 

Chief101

Chief Petty Officer
Joined
Sep 29, 2005
Messages
591
Re: Running with low speed can damage a 2 stroke engine ?

Yes, that i want to say, very slow , usualy i run in this way when i try to find a good place for fishing running near or above submerged trees because i don't want to broke my prop or scarring the fishes .

A.Cosmin

Bună dimineaţa A.Cosmin. You should be just fine as long as you are running at 5000rpm sometimes. Chief Chief
 

Salmonseeker

Petty Officer 1st Class
Joined
Jun 11, 2005
Messages
298
Re: Running with low speed can damage a 2 stroke engine ?

I troll all summer long for hours at at time with my Johnson 50HP 2 Stroke. Usually around 1000 RPM. Never had a problem. Like was mentioned above though. I do run WOT back to the ramp.

Jay
 

delfinasul

Seaman
Joined
Feb 15, 2007
Messages
69
Re: Running with low speed can damage a 2 stroke engine ?

Buna dimineata! Thank you all for help, i run with low speed only at fishing place , from my town to fishing place i run at 4700-5000 rpm's.

A.Cosmin
 

Chief101

Chief Petty Officer
Joined
Sep 29, 2005
Messages
591
Re: Running with low speed can damage a 2 stroke engine ?

Buna A.Cosmin! How's the carp fishing on the Danube? Not catching any here, do you have any baits or secrets to catching carps that you can tell me? Chief Chief
 

delfinasul

Seaman
Joined
Feb 15, 2007
Messages
69
Re: Running with low speed can damage a 2 stroke engine ?

Buna A.Cosmin! How's the carp fishing on the Danube? Not catching any here, do you have any baits or secrets to catching carps that you can tell me? Chief Chief

Not so good , water is still cold . About the bait , we use "mamaliga" si "rame albe"
(i don't know how to translate this terms in english i think the description for "rame albe" will be : earthen white worms :) ) and all fishermans i know use only this two kind of baits on Danube. A.Cosmin
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,392
Re: Running with low speed can damage a 2 stroke engine ?

I have to run for 10 to 15 minutes at very low speed at each end of my outing through the no wake zone to my dock. Running a 140hp Johnson V4 looper. No problems as of yet but as soon as we are out of the no wake zone up go the RPM !!
 

thurps

Chief Petty Officer
Joined
Jan 14, 2007
Messages
538
Re: Running with low speed can damage a 2 stroke engine ?

RPM's shouldn't make any difference as long as your pumping water. Carp, corn meal and strawberry jello made into a clay like paste.
 

Rob454

Chief Petty Officer
Joined
Oct 9, 2005
Messages
508
Re: Running with low speed can damage a 2 stroke engine ?

Mamaliga is a cornmeal mush. sort of like cream of wheat only made with corn. ( my wife is Romanian)
Rob
 

delfinasul

Seaman
Joined
Feb 15, 2007
Messages
69
Re: Running with low speed can damage a 2 stroke engine ?

Mamaliga is a cornmeal mush. sort of like cream of wheat only made with corn. ( my wife is Romanian)
Rob

Some fishermans put in mush, yolk for strenght, sugar,strawberry jello and different things very flavoured.
 

delfinasul

Seaman
Joined
Feb 15, 2007
Messages
69
Re: Running with low speed can damage a 2 stroke engine ?

Another question, i think when running a very low speed the engine will eat a lot of fuel on long distances(1-2miles) than running same distances with normal speed. This is true?


A.Cosmin
 

bassboy1

Lieutenant Commander
Joined
Jun 23, 2006
Messages
1,884
Re: Running with low speed can damage a 2 stroke engine ?

If you are concerned about carbon buildup then keep Sea Foam in your gas and don't worry about it......

However, if your boat is slightly under planing speed (big wake) when you do this you could be experiencing high combustion temps as you engine is under maximum stress..... which is not good. Dhadley can explain that for you.

If you are going slow enough that water is still in contact with the rear of the transom then go for it.

My 2c.

Mark
My 12 footer and 4 horse runs like that at WOT with dad and me in it. With just me, it is on the verge of planing. This won't hurt it will it? Please don't tell me yes, as I a) cannot afford any other motor, and b) have fallen in love with the 4 deluxe, and don't really want to change when I can afford it. How much jeapardy am I putting my motor in?
thanks, bassboy1
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,778
Re: Running with low speed can damage a 2 stroke engine ?

Guessing here on the 4 hp. Probably you have enough prop slip to allow the engine to run properly.

Gonna bet that small motors like that are designed to push big loads at WOT. A quick look at the prop tells you that.
----------------------
On MPG, your prop slip at slow speeds is hurrendous but your engine efficiency may be better.....but I doubt that engine efficiency can offset prop slip in terms of MPG. I did some tests on my rig once and prop slip "just on plane" was over 2.5x what it was at WOT. Under plane would be even worse.

Go to the Yamaha www and look at some of their tests for their different sizes of OB's. You should be able to get some slow speed ideas there.

Mark
 
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