props

[Tom D]

I owned a pontoon with an outboard for many years, but now I have my first
I/O engine - so different! I bought a pristine '97 SR2000 with a carburated
5.7L Alpha One that was installed in '14 and has had minimal use since.

1. Took it out for first time and at NO WAKE speed it did not want to go in a straight line - left, oversteer, right oversteer, etc. I'm hoping that it was mainly due to the Quiksilver 48 A521P prop. 2 other props also came with the boat -
Mercury A45P21 (3 fins) and a Mercury A4518P (4 fins). Help

2. This baby goes great at speed, but idles like a Harley, even quit twice at idle, then easily starts right back up. I called a local marine dealer and he said it sounds like he should rebuild the carburater for $450-500. I put a can of Seafoam in the gas tank to see if that would help, but I haven't put her back in the water yet. Thanks in advance for your Help

I am a new member on the Central Coast of CA

[mmwjr]

i would try quicksilver prop calculator to see what it recommends. The Alpha has a trim anode that is set to compensate for slow speed steering torque.

What carb do you have 2-4 bbl? At idle is the fuel a steady spray?

[Tom D]

So my trim anode is faulty?
I have a 4 barrel carb. I have not run the engine with the air filter cover off to watch the fuel spray - is it OK to do that, or is there a possibility of backfires?
Thanks Mike
Congrats on the Super Bowl win

[arichard]

My last boat had the same motor and outdrive on it with the anode like that. I can say that the reason your boat steers like that is due to you hull design in the water. Anode doesn't help. After 6 years I even replaced it with a flat one and no change. Take any boat with that design of hull which is a large percentage of them. They all do it. Just takes getting used to it.

As for low speed idle, Seafoam will help it, but nothing beats a carb rebuild. Even something most do it yourselfers can do with a little help online.

[shrew]

The prop would not impact bow wander. Bow wander is a result of over-steering. I find the detent for 'headway speed' is really a bit below 'no wake'. You can typically kick it 100 - 200 rpm and still be running at no wake. I can usually run up to 1,000 rpm and no be making a wake. The little extra speed reduces bow wander. The restis simply oversteering.

Prop size and pitch are dictated by RPM's at Wide Open Throttle. Most Mercruiser's max rpm range is between 4400 -4800 rpms.

[Tom D]

Thanks Richard. My boat has the exhaust pipes coming thru the transom above water level - very loud. Any suggestions on an affordable way to quiet lthem down?

[Tom D]

Thanks shrew. My boat has the exhaust pipes coming thru the transom above water level - very loud. Any suggestions on an affordable way to quiet lthem down?

[mmwjr]

Originally Posted by Tom D

So my trim anode is faulty?
I have a 4 barrel carb. I have not run the engine with the air filter cover off to watch the fuel spray - is it OK to do that, or is there a possibility of backfires?
Thanks Mike
Congrats on the Super Bowl win

Not faulty but not adjusted, you can set the leading edge to counter steering torque.

Always a possibility of backfire but if not doing so you can remove it for a short test anyway since you said it's an idle issue you only need to check it at idle.

[mmwjr]

Tom regarding the exhaust can you post some pictures of the exhaust from the inside. A aftermarket kit was installed some bypass the factory exhaust others are set up to go either way by a switch. Can you tell is the factory y-pipe is still there?

[shrew]

Originally Posted by Tom D

Thanks shrew. My boat has the exhaust pipes coming thru the transom above water level - very loud. Any suggestions on an affordable way to quiet lthem down?

That is not stock. It would have required that someone modified the Y valve that would divert exhaust and cooling water back through the transom assembly.

IIRC "Corsa" made a conversion kit. I think they might have even made a 'switchable' option to go between above water and outdrive exhaust systems.

The only real way to quiet that down would be to revert back to the stock exhaust configuration. Not knowing what has been done and how, I would have no idea what the cost involved would be.

[Tom D]

Thanks for the help arichard

[Tom D]

I will post pics as soon as we get some dry weather
Thanks

[Tom D]

So here are pictures that could help. Seems that there are units installed on top of the exhaust manifold and then a rubber hose that takes the exhaust out the back. The unit on the left side however, has some other mechanism attached to it. Looks pretty complex

[mmwjr]

No wonder it's loud piped right from the elbows to the transom with no mufflers at all. I do not see the y-pipe but it would be behind the engine right up against the transom. Most likely the PO installed a block off plate. The engine would need to be pulled to install a y-pipe.

[mmwjr]

Google mercruiser y-pipe to get the idea

[Tom D]

Originally Posted by mmwjr

Google mercruiser y-pipe to get the idea

Found used ones on eBay for $100.
Couldn't add mufflers to current system?
Thanks

Sent from my XT1650 using Tapatalk

[mmwjr]

Originally Posted by Tom D

Found used ones on eBay for $100.
Couldn't add mufflers to current system?
Thanks

Sent from my XT1650 using Tapatalk

Besides the y-pipe there are two rubber exhaust hoses and an elbow on each side.

[mmwjr]

Forgot the flapper valve and 8 hose clamps once again each side.

[speedysprocket]

And that complex mechanism is your shift cable from the helm to the shift cable for the drive. Three nuts and it comes off to move out of the way.

[Tom D]

Thanks guys