'96 Mirage Won't Accelerate, Taking on water

[rescue7043]

I have a 1996 SugarSand Mirage. I've had an issue with the boat not being able to accelerate above 10mph and when I do advance the throttle beyond a certain point I can hear the RPM's increasing, but the thrust is lost and the speed decreases until I back off the throttle. There are 2 parts to this issue that I will explain below.

Part 1: This happened last year, I took the boat in thinking the impeller needed to be replaced as I bought the boat used and had no maintenance records to go with. They ordered a new impeller for me, but stated that when they took the pump apart it appeared that there was no damage to the impeller or ring around it and did not advise on replacing at this point. They did notice that when I had the fuel lines replaced (previous owner only put the cheapest gas with ethanol in it and let it sit for 2 years) that the boat shop failed to put in inline fuel filter in. They replaced the filter, took it for a test run and it ran fine the whole rest of last season. Problem solved.... I thought.

Part 2: I've taken the boat out twice this year with NO issues at all, boat still running like a charm. Took it out yesterday expecting no issues at all. After traveling about 1 mile through Slow No Wake due to high waters on the river to the lake I finally got to the lake and opened it up. It was gaining speed, but could not get on plain and it felt like something was pulling it back. I opened up the hatch and the bilge is completely filled with water. I ran my bilge pump to clear out as much as I could and slowly made my way back to the ramp thinking maybe one of the drain plugs came out or was loose. I couldn't see an issue with water draining from where the drain plugs were once out of the water, but decided to remove them to drain the remaining water and I put in my brand new backup set of plugs just to be safe. While still on the trailer I backed the boat into the water and let it sit for a bit monitoring the bilge, could see no water coming in at all. Started the engine and same thing, so I thought I was good to go. Started my journey back on the river to the lake, constantly opening the hatch to check for water and it remained dry. Once I got out to the lake I slowly pushed the throttle and the boat would get to about 10mph and that's as fast as it would go. Open the hatch and see water in my bilge again. Can't figure out where on earth this water is coming from because any time I attempt to look there is already a descent amount of water in there and I can't see any flow.

At first I'm thinking a leaky seal that just needs to be resealed or replaced and I'll be back in business, but why wouldn't water come in when the boat is idling and only when under greater power. Also, why am I having this issue of little acceleration and high RPM's again. Are these two issues related or is it just a horrible coincidence that they both started at the same exact time? I know this boat is equipped with 2 tubes on each side of the pump(I've been boating my entire adult life, have a captains license and worked on mega yachts and I still have no freggin' idea what these things are called) that are supposed to suck up any water sitting in the bilge and flush it out through the pump when the boat is under power. They are faced towards the stern so I would guess that would help with any water in the boat so the bilge pump that is mounted forward of the engine doesn't have to work all the time. Could something be screwed up with these that when the boat is acting up the water is not being pumped OUT, but rather INTO the boat causing the water to come in?

I'm currently at a loss here. Will be taking the boat into the shop when I can get it in this week, but thought I would seek 'expert' advice on here first before having to search for my checkbook.


TIA for any and all assistance you can give.

 

[Stomp10]

@rescue7043
I have read through your post here several times.
I'm thinking that this one is kind of a head scratcher since no one has responded in almost 2 weeks time.

I keep coming back to a seal failure at the pump\hull connection but, that is a guess on my part.
Could you please share with the rest of us the diagnosis from the boat shop, once they get back to you?

 

[rescue7043]

I was surprised that out of all the views not a single person replied, even if it was something to say it was a complete mystery to them.
Everything in WI is backed up by weeks so the earliest I can bring it in is next Thursday.
Last time they had the acceleration issue fixed in a day so we’ll see. I was almost thinking the water issue could be where the water line comes up and connects with the engine for cooling. There is a threaded coupler that you can remove to connect a hose to run on the trailer. I’m thinking maybe that’s lose and letting water in. We’ll see I guess.

 

[Babin Farms]

I know nothing about SS boats but is the water warm like it's been through the engine? Sounds like it's a pressure leak with nothing visible just floating os going slow. Maybe take someone with you to drive the boat while you inspect for a leak at higher speed.

& make sure that you have the bilge pump on anytime that the boat is in the water.

 

[Stomp10]

@rescue7043

I was surprised that out of all the views not a single person replied, even if it was something to say it was a complete mystery to them.
Everything in WI is backed up by weeks so the earliest I can bring it in is next Thursday.
Last time they had the acceleration issue fixed in a day so we’ll see. I was almost thinking the water issue could be where the water line comes up and connects with the engine for cooling. There is a threaded coupler that you can remove to connect a hose to run on the trailer. I’m thinking maybe that’s lose and letting water in. We’ll see I guess.

Well I was compelled to give a response.... Hate to leave a guy hangin!
Best of luck and hope it's an easy fix!

 

[Blkrvrbart]

Hey @rescue7043. Some other folks on here had a similar issue. If you have the 175, there’s a plate on the side that is known to leak, just takes a new gasket. I don’t have a 175, but have seen this problem through @WILL IHNE ’s experience at least if I remember correctly. Kind of a hassle to get to, but I would start looking there. There is a suction drain that works when the engine is running as long as the screen isn’t clogged. It is a gray hose about 1/2” or 5/8” o.d. that loops over the top of the motor down to the floor on the starboard side.
I hope you figure it out. Sorry it took me a while, and hope I’m steering you in the right direction.