[myotherhorse]

New owner here of a 1994 Mariah. Love the boat, finding out about all the hiccups along the way. First day out while taking a break sitting on the platform, I felt like the back of the boat was going down. Right after that the bilge pump ran. All we had done was go up and down the lake a few times.
So we thought that was odd that the pump ran, how could it have taken on enough water to run. Than while sitting there and swimming near the boat, the bilge pump ran at least two more times. The previous owner had said we could call with any questions and so we did. He claims the boat has always done that since he brought it new. But, how could there be water coming in the boat when we are just sitting still and yet he claims it did this from new. He did mention there is hose on the outside that could get a crack in it and we should check that, but I can't understand that the boat would need to run the bilge pump and expel water over and over, when it is just anchored for maybe an hour at most.

[Andy b]

Most probably your bellows, although you could have a leak in any part of your cooling system.
another place to look is the gasket between the exhaust and the transom shield. had one of them go before. best thing is to put it back in the water and get a touch out.
Does the boat take on any water whilst running the engine in muffs?

[ColoradoDiablo]

That is not normal!
If it's taking on water that fast , you better find the prob and find it fast!
As Andy asked , does it take on water while running on the muffs in the driveway?
Check all the boots , especially the shift cable boot.
If you have a split/leaking boot , it will take on water whether it's underway or not.
It's basically just like drilling a hole in the side of the boat!

Sounds stupid , but the plug is in and in good shape isn't it?

[Andy b]

Originally Posted by ColoradoDiablo

Sounds stupid , but the plug is in and in good shape isn't it?

Not stupid at all... that's boating mistake 101
we've all done it

[Lucky14]

Do you have to activate the switch on the console to turn the bilge on? Or is that switch a manual override to the automatic activation of the bilge- I'm a nooooooooobie.

[ColoradoDiablo]

They installed them both ways. Some Auto with float switch and a manual switch at dash , and some just manual only. Looks like after 1993 , the Mariahs were all equipped with auto/manual bilge pumps.

[Lucky14]

Thanks!

[myotherhorse]

Hi, Yes, plug is in and tight.
Found one hose clamp that did not seem too tight, tightened
that, tried again and still taking on a lot of water. Almost seems like it is worse
when we are sitting still on water. Tried looking under engine with flashlight
while spraying with hose on dry ground and also watching while in the water
and could not see any water coming in, but it is coming from somewhere!
Bilge runs automatically. However, last trip out, after it ran we ran the manual override
and a LOT more water pumped out. Till we docked, maybe 1 hr later, it ran again at dock,
and when we undid the plug...gush gush gush, a LOT of water! Do I have to remove the outdrive to
find the source at this point?

[myotherhorse]

It does not take on water while running with the muffs.
Any more suggestions? Finally found a boat that suited our needs, price and
seemed to come from a honest person. Original owner from new who moved
on to a pontoon. Only few weeks left of summer weather, hate to take time to
rip apart, but would hate even more to sink! Especially with my grand children on board!

Also I was wrong about previous owner saying the bilge pump ran that much. He did however,
tell us when what I thought was a lot of water after the trial run coming out after plug was
removed, that it was because he got caught in a lot of rain on way to lake, and it had rained
quite a bit so we believed him.

[mikeyt]

Sounds like you are down to a split in your drive bellows or the shift boot. My bet is on the drive bellows. To replace it you need to remove the outdrive and while you have the outdrive off you may as well inspect the gimbal bearing as well as the u-joints for wear. Removing the outdrive & doing these repairs is for the mechanically inclined. This is not something you will want to leave for any length of time or you may find your boat on the bottom of the lake.

Here's a link to a step by step instruction on doing this job so that u have an idea what you are up against if you are planning on tackling this one yourself.