Is running at low RPMs for a long time "bad" for the engine

[CurrentObsession]

Re: Is running at low RPMs for a long time "bad" for the engine

That action, against the splines, Wears the splines...
Skip greasin' the splines a year, 'n you'll need a coupler, cause the splines wear out....

Where are the splines on a BIII? A diagram would be awesome....

 

[dubs283]

Re: Is running at low RPMs for a long time "bad" for the engine

the splines that wear are in the coupler, mounted to the flywheel of the engine

factory are aluminum and without annual maintenance they will fail

 

[cyclops2]

Re: Is running at low RPMs for a long time "bad" for the engine

Dubs

What a wonderfull built in repair job. I am glad I have the marina do the scheduled maintainance. They must be doing it right on the 2002 5 L or It would be toast by now.

 

[LilRedNeckGirl]

Re: Is running at low RPMs for a long time "bad" for the engine

Arghhhh, ... slow rpm runs do not hurt an engine. its the 2 strokers that have issues with that, but thats only because of potential oil build up due to the oil mix in the fuel.
then there is the ' it wears out this and that' ... it might, but isnt that why they make 'replacment' parts?
you gotta do a no wake speed at times, fishing is ofeten trolling, the evening dinner cruise isnt at wot, @ boats were designed for this slow speed.
then, God said, let there be winter, so that every boater has the time and oppertunity to inspect, repair and maintain his vessel.

 

[CurrentObsession]

Re: Is running at low RPMs for a long time "bad" for the engine

the splines that wear are in the coupler, mounted to the flywheel of the engine

factory are aluminum and without annual maintenance they will fail

So how does one go about getting grease to them? Is it as simple as a zerk fitting?

 

[Don S]

Re: Is running at low RPMs for a long time "bad" for the engine

What a wonderfull built in repair job. I am glad I have the marina do the scheduled maintainance. They must be doing it right on the 2002 5 L or It would be toast by now.

It's not a "Built in repair job" it's how splined shafts are hooked to things. Both land based and marine. All it takes is making sure things are aligned and lubricated (known as preventive maintenance), and they last for many years.

Since it is in the manuals, to lube the splines every 50 hours if used with prolonged idle periods, it kind of pokes holes in your story about your talk with a customer service rep.

 

[achris]

Re: Is running at low RPMs for a long time "bad" for the engine

So how does one go about getting grease to them? Is it as simple as a zerk fitting?

Newer models have a grease nipple, yes. For older models, pull the drive and grease the splines and the coupler... It's called 'annual service'....

 

[cyclops2]

Re: Is running at low RPMs for a long time "bad" for the engine

Well Don, since you were not sitting next to me during the tech call. There are no holes in my story with him.
We may also be not using the same standards for idling.
Idle to most people is in neutral, or rarely, idleing in gear.
Using a main engine in neutral to meet all equipment electrical needs while stopped or anchored is not the same as sustained No Wake Zones rpms in foward gear. I realize rolling all 3 conditions together is common. But No Wake Zone speeds & above 1,000 rpm is not idling.

Edit.
We are rolling idle speed into the term of ... off idle... easy to do. + 1,000 rpms is definately off idle & not part of a 50 hour requirement.

 

[dubs283]

Re: Is running at low RPMs for a long time "bad" for the engine

So how does one go about getting grease to them? Is it as simple as a zerk fitting?

like chris says, yeah there is grease zirc on some newer ones - but are kinda tough to get to in some boats, also you have to make sure the engine has stopped in the right spot to access it (might be on the bottom)

i have never used the zirc on a merc coupler becuase pulling the drive is the best way to do it - it gives you the chance to inspect more of the transom assy

 

[cyclops2]

Re: Is running at low RPMs for a long time "bad" for the engine

I was able to find this 2007 coupler lubricating chart. My 2002 Alpha is supposed to have the "" sealed "" ??? coupler.
How the heck would ANY SEALED part ever need to be greased ????????
Mercruiser has their own dictionary.
No wonder people believe a newer coupling does not need greasing. They see the words " sealed " and " Permalubed ".

Go right to the next step of maintainance.

Don
Mercruiser can not even agree on the # of hours the couplers need lubing if a lot of idling is done. Notice the difference between Bravo & Alphas.
Different people have different ideas what a " lot of idle is ".

Mercruiser is very non commital about determining idle hours. Why not make all drives the same greasing period / time, to elimanate new mechanics / owners, forgetting which drive is which. I blame the, Chief, for such confusing maintainance scheduales.

 

[cyclops2]

Re: Is running at low RPMs for a long time "bad" for the engine

Here is the page from the 2007 manual.

Site preventing the download.

 

[dubs283]

Re: Is running at low RPMs for a long time "bad" for the engine

mercruiser cannot give a magic cure all answer because people use their equipment differently

they can only give estimates and ranges because that is what they have determined to be suitible required maintenance for their products

if they were that specific then someone could claim that they waited for "x" number of hours before maintenance based on exactly how mercruiser defined their use of the product and would have to warranty it if it failed before reaching "x" number of hours

bravo and alpha drives are completely different products, which is why they require different maintenence intervals

 

[Don S]

Re: Is running at low RPMs for a long time "bad" for the engine

Site preventing the download.

Yes, it's broken, and there is a yellow bar across the top of every page explaining why. unless you clicked the X.
If you have a picture, use photobucket.

 

[QC]

Re: Is running at low RPMs for a long time "bad" for the engine

Idle speed in gear for no wake zones is VERY common in high speed boats. Many can't go slow enough at idle and have to be pulled out of gear on and off just to keep speeds down. If you haven't seen this, you haven't boated around many boats faster than 50 MPH. You simply can't prop for high speeds and also run at 1000 RPM in no wake zones

To second what dubs is referring to, Manufacturers have a big issue dealing with solid maintenance recommendations that work for all applications. A 50 hour interval is ridiculous for a commercial guy, but covers pleasure craft really well. Think about the truck business How can you recommend a mileage interval for a on-highway tractor that averages over 45 MPH and a refuse truck that averages 7 MPH? You can't. So go with hours. OK, but are idle hours the same as full load? Of course not. So let's use gallons of fuel. But maybe that's no good because some light load points are bad for certain components uhhhh . . . coupler and splines? Hmmmmmmm. They do the best they can for the variety of applications they deal with. Ohhh, and as far as planned repairs. They can make a coupler and shaft combination that will never need maintenance, you just can't afford it

 

[Don S]

Re: Is running at low RPMs for a long time "bad" for the engine

Mercruiser is very non commital about determining idle hours. Why not make all drives the same greasing period / time, to elimanate new mechanics / owners, forgetting which drive is which. I blame the, Chief, for such confusing maintainance scheduales.

The 50 hour spec is for all drives, it's the same in the Alpha service manuals, and the Bravo service manuals, same in the Alpha and Bravo owners manuals. I have some from 2000, 2002, 2006, and 2008 and they all say the same exact thing.
For prolonged idle, grease the splines and gimbal bearing every 50 hours. A little common sense goes along way in this too. Since most boats don't have hour meters, you kind of have to guess. But if you do a lot of idling, or low rpm operation, it sure won't hurt to lube a little more often.

 

[cyclops2]

Re: Is running at low RPMs for a long time "bad" for the engine

I keep receiving." You do not have access to this page ". Posting a picture.

From the Manual...
Note: If the boat is operated at idle for prolonged periods of time, coupler should be lubricated...BRAVO MODELS - every 50 hours; ALPHA MODELS - every 150hours.

It is on page 29 of 56 pages,

Frpm www.mercurymarine.com

 

[cyclops2]

Re: Is running at low RPMs for a long time "bad" for the engine

Don

I just noticed my quote is also in section 5 Maintenance . Talk about the inconsistancies ??

 

[cyclops2]

Re: Is running at low RPMs for a long time "bad" for the engine

My documents look like a legal PDF. The responsibilities of a owner & a dealer are spelled out. Even including D I Y maint. Suggestions.
It looks like a document # of... 90-899883179-Maint.pdf

Could you check it out ?

 

[Don S]

Re: Is running at low RPMs for a long time "bad" for the engine

:facepalm: :facepalm: :facepalm:

 

[dollarten]

Re: Is running at low RPMs for a long time "bad" for the engine

Depending on how new or old your boat is. If you can look at the area where the drive coupler is , there might be a grease fitting . It would appear that it is screwed right in to the bell housing or , flywheel cover if you will . On older models you will have to take off the drive unit and grease them . While you have the drive unit off , you can check the engine alignment too