Engine shutdown procedure VP 8.1 Gi-J

[ChooChooSnakeMan]

Hi Everyone, I'm looking forward to getting boating season kicked off here soon and getting the Ebbtide 2660 Ztrak with an 8.1 Volvo Gi-J in the water for the first time. I've read a lot of posts in various places about water injestion for these engines. I see some statements that are confusing, at least to me. Some statements seem to say that it is only a concern for engines operated in salt water which mine has not nor will be. I also see that maybe there was a model year that the problem stopped. My engine is a 2011. I also see that some people say that they run the engine out of gear at 1500 - 2000 rpm for 20 seconds to heat the exhaust and evaporate any condensation and they shut the engine off with the key while running 1500-2000 rpm. I want to follow the right procedure. I note that my engine manual says to not turn the engine off at any rpm more than idle and I can see where shutting down at high rpms might create problems with sensors. So to all you VP gurus out there, what say ye? What has been your practice? Shut off at idle speed or shut off with higher rpm? Or maybe you do something different. Maybe it was only a problem in salt water or prior to my model year of 2011. Your input is appreciated. Thanks

 

[Bt Doctur]

dieseling or run-on is caused by;
high engine temps
poor octane/fuel
incorrect timing
shutting engine off at above idle speeds

usually after a sustained run you run the e=engine in neutral to dissipate the engine heat then return to idle and shut off

 

[ChooChooSnakeMan]

dieseling or run-on is caused by;
high engine temps
poor octane/fuel
incorrect timing
shutting engine off at above idle speeds

usually after a sustained run you run the e=engine in neutral to dissipate the engine heat then return to idle and shut off

Thank you for your reply. So what you are saying makes sense to me, just before shutdown run the engine above idle speed for a short time to burn off any condensation but return to idle rpm before shutting the engine down. There were posts that were specific to run the engine at 1500 to 2000 rpm and shut it down while running the higher speed but to me common sense says that wouldn't be good for the engine systems. I hope there will be more input from others about this. I hope that if VP took care of this issue with maybe a different exhaust riser design that someone will post which model year it no longer was an issue. Again, thanks for taking the time to reply.

 

[alldodge]

I have not read anything that makes a stock 8.1 more prone to reversion then any other motor. If the motor has not been changed from when it came from the factory there should be no issue.

As Bt Doc mentioned, if the more is not in tune and running hot this can cause problems for any motor. If running hot when motor is turned off it may run backwards and suck water in. A well running motor should have none of these issues.

Run your motor like any other, and don't run high rpm then shut down

 

[Grub54891]

Idle it for a few minutes and shut down. My procedure for years, no issues. It gives the motor time to cool down. I always laugh when I see others shut down when drifting into the dock and then the wind gets ahold of them, and they have to re-start. Never shut down at higher than idle and till the lines are secure.

 

[BRICH1260]

I think you are overthinking the situation. Water ingestion is not that common and unless someone has modified your exhaust system, I would not worry about it. I would advise not to come to a sudden stop after traveling at speed to avoid a high backwash against the transom.

 

[ChooChooSnakeMan]

I think you are overthinking the situation. Water ingestion is not that common and unless someone has modified your exhaust system, I would not worry about it. I would advise not to come to a sudden stop after traveling at speed to avoid a high backwash against the transom.

Thanks everyone for your input. I feel much better about the situation. To be clear there are a lot of posts from early 2000 year engines that had issues. Water injestion was part of the problem but as mentioned I think that was either a poor designed exhaust system (risers not tall enough) and / or cutting the throttle suddenly from high speed and causing a lot of back flow into the engine from a high water level. The problem I'm most concerned with are all the posts about the exhaust design and cam overlap on unmodified factory engines and boat builder installations causing condensation from a cooling off engine when idling forming water droplets that get into the exhaust ports on the engine. That is why some people posted that they actually run their big block VP engines up to 1500 - 2000 rpm for 20-30 seconds to heat everything up and evaporate the condensation before shutting down. I've re-read the posts and they say they shut down from the high idle rpm. At least one poster says they have done this religioulsy for years and their engine has had a long life. It is an interesting subject. Since you all have not had an issue I will adopt the normal shutdown procedure that I have used with my outboards for many years. Just let it idle for a minute or so, which usually happens naturally as you idle in to dock and not worry about water condensation in the exhaust getting into the engine. I appreciate the comment about not shutting down until you are secured to the dock. This is my first big boat and first without a trolling motor. The trolling motor on bass boats is nice for maneuvering around docks and I'll have to master not having one.

 

[Lou C]

The usual causes of this are:
Leaky manifold to elbow gaskets —are there rust stains in the joint between the manifold & elbow?
Elbows are not high enough above static waterline level (at least 13-14”)
Engine camshaft specs with too much overlap (if engine was rebuilt)
You can raise idle speed to heat the exhaust but I’d drop it back to idle before switching off.

Also Volvo used what would be considered a cold manifold design; and at idle they can run as cool as 95-100*F; make sure your engine has the right thermostat & is fully coming up to normal temp. If running cold it will make the formation of condensation more likely.

 

[cyclops222]

Idle for a couple of minutes . IF IF you come up to your dock at at w o t and a fully overheated engine. You will not have condensation in a engine that has run for 15 minutes or more. THe shutting down a higher idle speed. DOES allow RAW unburned gasoline to build up in the cylinders. Bad
Turning it off at idle BURNS UP all the gasoline mixture in the cylinder. Do it that way. Low Octane gas & screwed up timing will also cause the rough after running. The engine is firing by compression. The ignition key can not stop the engine it circulates enough COOL WATER thru it.