Recommmended Engine Warmup

Todd320

Well-Known Member
Jul 21, 2016
1,508
St. Petersburg, FL
Boat Info
2007 Sea Ray 320DA
Engines
Twin V-drive 5.7L 350 Horizon
My mechanic has asked me to warm my 07 5.7L engines up at 1000 rpm until they reach operating temperature. Not sure if anyone else has heard this recommendation but I thought I would pass it along. I am not sure on the why, or if this is common knowledge, he made it sound like this was a recently new (last 3 or 4 years?) recommendation from MerCruiser.
 
I start them and just let them run until they reach the temp. Did he say why they should be reved up? My engines are 17 years old and purr like a cat, so I won’t change what I do, but wondering why.
 
Yuck....sounds like the opposite of what my brain tells me would be best??? I want those motors running as slow as possible until they are up to temp. Unless you're not getting proper oil pressure at idle I can't think of any reason to rev them?

If I heard a dock neighbor start their boat and kick the throttle up and leave it I'd probably 1.) think they had too much to drink and 2.) go ask them what's wrong with their boat. :)

Of course my boat is antique these days. Maybe there is a reason to do this....I've just never heard of such a thing.
 
a guy near us used to start his boat ice cold and let it run at almost 3,000 RPM until it was warmed up. Craziest thing I've ever seen. Of course, he had zero problems with it during the time he was down there yet somehow my incredibly maintained boat blew a drive that year so maybe he was on to something
 
1000 RPM is not all that high, But I would let them run 1 or 2 minutes before bumping up to 1000 RPMs. I never run mine up to operating temp before heading out, but rather just enough to make sure they don't stall while pulling out of slip.
 
When I bought my boat the delivery captain said start it in the slip let it idle for a minute or two and then start untying lines. By the time you idle out of the marina you are good. He did say if going slower (Out of the marina) to be at least at 1600 rpms would be better for the transmissions.
 
I’m guessing maybe he’s thinking a lot of these MerCruiser motor are prone to water ingestion especially at very low RPM you get misting coming back with the exhaust pulses but if you bump it up to 900 or 1000 RPMs there’s enough pressure to push out the mist there was actually a MerCruiser bulletin about how to not run your motor at idle for extended periods of time remedy was to run your boat at 1000 RPMs for a minute or two to dry up and push out any water that worked its way back to the exhaust valves
 
I’m guessing maybe he’s thinking a lot of these MerCruiser motor are prone to water ingestion especially at very low RPM you get misting coming back with the exhaust pulses but if you bump it up to 900 or 1000 RPMs there’s enough pressure to push out the mist there was actually a MerCruiser bulletin about how to not run your motor at idle for extended periods of time remedy was to run your boat at 1000 RPMs for a minute or two to dry up and push out any water that worked its way back to the exhaust valves

This sounds like advice for a specific type of exhaust system that does not have water lift mufflers. Out of respect to neighbors, we generally get the boat ready to leave by stowing power cords and lines. When that work is done, we start the engines and idle out of the slip at 650 rpms give or take a little. If we kicked it up to 1000 our wake would draw complaints. At 1600 rpm, the sheriff would soon be tied up to our boat writing a ticket. We have a 7 mile long no wake zone from our home slip to Lake Michigan. We are at cruise temps long before we get there. Many times our boating consists of putzing along at 5-6 knots due large waves on Lake Michigan.
Maybe your warm up procedure depends on the engine exhaust set up you have.
 
Sorry I was not recommending to run your boat at 1000 RPM in a no wake zone what I meant was maybe the mechanic was recommending upon start up bumping the idol up slightly also upon returning from long runs in no wake zone’s the bulletin recommended once you are docked before you shut down your motor to allow it to run at 1000 RPM for 1 to 2 minutes then slowly dropping the throttles and shutting off the motor to dry up any exhaust mist that has settled I added the link in case anybody wants to read up on it maybe you could help somebody out http://www.boatfix.com/merc/Bullet/01/01_13.pdf

runrecommendedQUOTE="sbw1, post: 983440, member: 506"]This sounds like advice for a specific type of exhaust system that does not have water lift mufflers. Out of respect to neighbors, we generally get the boat ready to leave by stowing power cords and lines. When that work is done, we start the engines and idle out of the slip at 650 rpms give or take a little. If we kicked it up to 1000 our wake would draw complaints. At 1600 rpm, the sheriff would soon be tied up to our boat writing a ticket. We have a 7 mile long no wake zone from our home slip to Lake Michigan. We are at cruise temps long before we get there. Many times our boating consists of putzing along at 5-6 knots due large waves on Lake Michigan.
Maybe your warm up procedure depends on the engine exhaust set up you have.[/QUOTE]
 
I’m guessing maybe he’s thinking a lot of these MerCruiser motor are prone to water ingestion especially at very low RPM you get misting coming back with the exhaust pulses but if you bump it up to 900 or 1000 RPMs there’s enough pressure to push out the mist there was actually a MerCruiser bulletin about how to not run your motor at idle for extended periods of time remedy was to run your boat at 1000 RPMs for a minute or two to dry up and push out any water that worked its way back to the exhaust valves

I'm going to use this excuse next time. Sorry, honey. There was a technical bulletin that said misting could occur if we idle too long. Something about misting being ingested up the exhaust pipe? So we need to skip the foreplay and bump it right up to 1,000rpm.

;)
 
Excerpted from Mercury Service Bulletin 2001-13 (google it for the entire bulletin):


Screen Shot 2018-04-17 at 7.51.47 AM.png
 
I always let my engines warm up to temp before pulling away from the dock. If I don't they sometimes will stall, not good in close quarters during windy conditions. My routine is to run the blowers for 5-10 minutes, then start the port engine then the starboard engine. I let them idle while I prepare the boat to get underway. I cruise out of my dock at idle and when I get to the end of my canal and on the fairway I bump up tp 1000 rpm until I get to the ICW.
 
i start the engine , open the hatch to take a last visual everything sounds and looks good with engine idling and leave the dock . before giving full power i in any case wait for reaching operating temps even considering the oil needs longer to warm up - so first 10-15 minutes after leaving the dock only cocktail speeds .

i never fully warm waiting at the dock but guys with a carbed engine wich tends to stall cold may need another procedure
 
For me it just depends if the dock is busy of not.

I'm on a dock with mostly ski and pontoon boats so when no one is around I may let the boat idle a little more while parked other wise I start and allow them to idle while I untie and disconnect and then putt out of the marina. I smoke a bit on start up when the boat sits for a week or so so I don't want to be annoying to other boaters.

If I was located on a dock with other cruiser boats I probably would change it up a little to avoid CO problems with neighboring boaters.
 
We have a 7 mile long no wake zone from our home slip to Lake Michigan. We are at cruise temps long before we get there. Many times our boating consists of putzing along at 5-6 knots due large waves on Lake Michigan.

OMG. I thought the miserable mile in Cape Coral was intolerable. I can't imagine 7 miles of no wake to just get on the real water.
 
The miserable mile in Cape Coral gives us PLENTY of warmup time!! LOL!

With 10 gallons of oil each, our warmup time is long anyway. My oil temps under load are around 225, and I don't go above 1000 RPM until I get to 180.
 
Being a carbed engine I wait till the engine hits 140*. 2 years ago we had a couple of times the boat stalled due to not being warmed enough. The wife liked to start untying as soon as the boat started so I just went with it. Ended up rebuilding the carb and it still did it. Started asking around and just experimenting and found that if I just let it warm up it was fine. Others said they let theirs idle until warm too. Mine usually takes around 10 minutes to reach 140* (normal temps are 160*). I might be ok at 120* but haven't tried. It works at 140* so thats my target. We have about 1/4 mile to the end of the no wake so we are completely up to temp by then.
 
my routine is to let my engines warm up to full operating temp before leaving the doc...this only takes a few mins and gives me time to prepare the boat for leaving the doc...and it has some advantages...

three advantages:
1. less chance for stalling from cold engines...this is especially important if it is a windy day....
2. sometimes a problem with an engine at idle does not show up until the engine is at normal operating temp and the ECM goes into 'closed loop' mode....this could be from a defective sensor....if there is a problem like this I would rather be at the dock than a mile away from the dock....
3. if one of the engines overheats at idle from a mechanical problem (such as a bad impeller) I would rather it be while I was at the dock than a mile away from the dock

cliff
 

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