Twin Engines not used equally?

[NDMatt]

Hi everyone, I'm thinking about buying a boat with twin 5.7L engines. Boat looks great, but I have one nagging issue. The engines don't have the same amount of time (450 vs 550 or so) and the seller is saying it's because one engine was turned off while idling down the river. Is this normal? Will it damage the engines/drives to only use one engine? And even if you are only using one engine, why not alternate to keep the engine wear equal?

Thanks,
Matt

 

[Turtlesboat]

is it normal? doesn't sound like normal behavior. Is it possible? yes.

He could have had problems with one engine and limped back home, some boats the hour meter will run if the key is in and turned on, sometimes guys will troll for fish on one engine. does the engine with the power steering hooked to it have more hours?

 

[Stray Cat]

When gas was $4.00 + a gallon, there were quite a few people that did what the PO claims. Does this boat have outdrives or V drives? The reason they don't alternate between both engines on outdrives is the power steering may run off of one not both engines. A hundred hours is right at a boating season for the midwest.

It will not hurt anything to only run one engine, but I would have a surveyor hired by yourself to investigate it further and take a seatrial if you get serious about making an offer.

I always run both....I have around 20 minutes difference between them.

 

[my3sons]

I would also say that it is not "normal" to operate on one motor, however we are near the Erie Canal, and I do know of some boaters that have stern drive boats that cruise the canal on one engine, and as Mike and Jeff said, they run the one with the power steering.

 

[David Morgan]

I have a hydraulic PTO on the port engine on the boat I run for a living. It has more engine hours because I frequently need to use the hydraulics when stopped and it makes no sense to keep the starboard engine idling doing nothing.

 

[Hampton]

You say drives. Are they I/O? If not, and they are V-drives, make sure they have the shaft seal crossover lines to cool the one on the side of the stopped engine. If not, it's probably shot. We need more details. Boat type. Drive types.

 

[northern]

With twin inboards at 6 knots I burn 1 gallon an hour. If I turn off one engine I go 4.5 knots and burn 1/2 gallon an hour. Only did this once when I had a starter fail. It did not seem to hurt the transmission or seal on the non running engine but it was difficult to dock. I know of people that only run on one engine when in the open. It depends on the transmission and seals what if any damage will be done. Your transmissinon will turn backwards and the out board bearing on the transmission that is notmally a thrust bearing will change the direction of thrust. Ask the mechanic who serveys your boat and post his answer so we all can know.

 

[Jimmy Buoy]

You say drives. Are they I/O? If not, and they are V-drives, make sure they have the shaft seal crossover lines to cool the one on the side of the stopped engine. If not, it's probably shot. We need more details. Boat type. Drive types.

Shaft seals do not require a cooling line if they never go fast enough to get on plane (for displacement hulls). Running a V-drive with one engine would would NOT likely ever get on plane (I'm sure that it would not be desireable to run more than 1500 - 2000 RPM anyway on the one engine). With your hull speed being so low, it shouldn't hurt the lip seal with the shaft spinning since cooling water wouldn't be abscent from behind the seal until reaching faster speeds.

That being said, the tranny fluid may be more of a concern. Many units require the engine to be running to distribute fluid to the gears and the heat exchanger. No fluid = Broken Tranny.:smt013 A tranny is MUCH more expensive to replace than a shaft seal so if it's a V-drive you want it checked!:thumbsup:

I/O's should be unaffected.

 

[NDMatt]

Thanks for all the responses. The boat has I/Os with Bravo I drives. The more I read, the more sense it makes that the engines don't have the same hours on them.

 

[berth control]

I troll for Salmon on one engine to get the boat going slower, two is too fast. I will also run just one engine to charge the batteries if on the hook for a while, so mine are about a hundred hours different, but they came that way.

 

[flflatrate]

are the motors in the boat you are looking at MPI's, if they are you might be able to hook up the computer and see the running history to see if that is true and where the differences actually are in the rpm range