Islandia seems short on power...

[pgilchri]

2000 Islandia with 240 merc. sport jet.

Got it last fall. Has a quicksilver remanufactured engine with approx 12 hours on it. FYI Had an issue with the diaphragm fuel pump right off the bat (kept loosing fuel pressure and engine would die after running high rpms). Replaced and it seems to have solved the problem.

The issue (I think) I have is I am only able to hit around 34 mph (GPS) at wot (5900 rpm) with a moderate to light load on the boat. From what I read I should be able to reach the low 40s. Is this correct?

Last weekend I tried to take the extended family out with a full load (6 adults and 5 young kids plus a cooler), and it didn't go very well. We couldn't even plane out and only could hit around 13 mph. I know we were pushing the weight limit for the boat, but I'm thinking it should at least plane out.

Inspected the impeller which looked really good to me (no big nicks or excessive damage that I could see. I measured .020" of clearance between the impeller and wear ring. Believe this is acceptable from what I remember reading. One thing I did notice is wear on the wear ring on the top of the ring, but not the bottom. Is this normal? Pic of impeller is attached.

Peered into the stator from the rear and could see some wear but again nothing that seemed excessive or strange to me.

I checked the lube in the gear box and it was as clean as the day it was put in.

I have not gotten to the stator oil yet.

Does anyone have any words of wisdom on how to proceed?

Thanks,

Patrick

 

[Dr Honda]

I see the thread is "Islandia"... but your signature says "Utopia." just want to verify what boat we are talking about.

Assuming either boat... yes... it should be running faster. (low 40's)

When you had a full load in the boat... was it sitting nose high when you were trying to go? I know when it's hot... everyone wants to be under the bimini top... and there is too much weight in the back. There has been several times where I have to tell an adult or two to move to the front. After balancing the boat better... it goes without an issue.

From your pic... it looks like the wear ring isn't centered. (it's rubbing the top, and has clearance on the bottom) Cavitation can come from several sources... and one that people don't think about is sucking air around the pump. I'm wondering if the sections aren't sealing. If it was my boat... I would take the rear section apart, and get a better look at everything... clean everything... and then put it back together. (making sure it's all sealing)

 

[pgilchri]

Dr. Honda,

Thanks for the response. Yes I made sure the load was balanced with people up front too. In fact we tried redistributing the load several times to try to get it to plane out.

I like your idea about disassembling the rear of the pump to check things out. In fact I already have the bolts soaking in penetrating oil. I also have the two o rings on order as I am planning on replacing them when its all apart. Anything else I should plan on replacing while I'm in there?

For a quick clean would steel wool be appropriate?

BTW I fixed my signature, not sure what happened there.

-Patrick

 

[Tim75]

Dr. Honda,

Thanks for the response. Yes I made sure the load was balanced with people up front too. In fact we tried redistributing the load several times to try to get it to plane out.

I like your idea about disassembling the rear of the pump to check things out. In fact I already have the bolts soaking in penetrating oil. I also have the two o rings on order as I am planning on replacing them when its all apart. Anything else I should plan on replacing while I'm in there?

For a quick clean would steel wool be appropriate?

BTW I fixed my signature, not sure what happened there.

-Patrick

Do not clean the impeller with steel wool or anything else on a boat. You will make it rust. You will mechanically push iron into the surface of anything steel wool touches. You can use maroon Scotch-Brite. $3/pad at West Marine or $25/box of 20 on ebay.

While you have the stator off, remove the wear ring. You only need about an inch. Don't remove the steering cable unless there is a problem with it. You are looking for any kind of buildup that would make the pieces not sit flat and parallel to each other. Between the intake casting, and wear ring. Between wear ring and stator. Such as excess paint or sealant or an o-ring out of position. Possibly one bolt was tightened before the others? Also need to visual the bearings in the stator.

 

[pgilchri]

Tim75,

Thanks for the tip on using Scotch-Brite pads. I ordered up a box.

I do have a follow up question; what exactly do you mean when you say "you only need about an inch." Is it in reference as to how far to pull out the wear ring?

Just throwing this out there, but would a small amount of RTV sealant help seal everything up here? Or would it just make future repair a nightmare?


Thanks for the help,

Patrick

 

[Dr Honda]

RTV will make future service a big pain in the butt. You should have it apart once a year for service.

 

[Tim75]

Tim75,

Thanks for the tip on using Scotch-Brite pads. I ordered up a box.

I do have a follow up question; what exactly do you mean when you say "you only need about an inch." Is it in reference as to how far to pull out the wear ring?

Just throwing this out there, but would a small amount of RTV sealant help seal everything up here? Or would it just make future repair a nightmare?


Thanks for the help,

Patrick

Room to check behind wear ring. You may need to loosen the hose clamp in the bilge. A thin coat of rtv on the large o-ring helps seal and is still easy to disassemble.

 

[pgilchri]

So I disassembled my pump this afternoon.

Two things seemed out of sorts to me.

1. the small o ring was missing between the wear ring and the water intake. Could this be a source of air? (I believe this feeds cooling water to the engine so I’m not thinking so but does anyone have any thoughts?)

2.As I slowly loosened the bolts holding on the stator (and they were very tight) I could hear some movement even as there was a fair amount of pressure on the bolts. Maybe there was an ever so slight alignment problem???

Otherwise everything looked really good. Stator vanes were in good shape. Large o ring looked in good shape. Wear ring and impeller were good.

Did see some evidence of a very small amount of water in the stator. Is this normal? God only knows how long the oil was in there.

Thoughts?

Thanks,
Patrick

 

[Dr Honda]

Actually looks pretty good.

No... the missing small o-ring shouldn't be an issue with air leaks... but it could leak water, and drop pressure to the engine.

You shouldn't have any water in the stator... but was it mixed with the oil? or was it just a splash sitting around the seal? If there is a question about that... now is the time to replace the seal and bearing since it's a part.

 

[pgilchri]

Yes it was mixed. The oil didnt look "pure" like the gear case oil did. It had just a hint of milky color which I have seen before when water mixes with oil.

 

[Tim75]

Yes it was mixed. The oil didnt look "pure" like the gear case oil did. It had just a hint of milky color which I have seen before when water mixes with oil.

Now is the time to replace the shaft seal in the stator. Since it's already apart, it will take about another minute.

Your intake grate-time to replace it. Your system looks good now, but when those tines break off (as they are known to do) and try to pass thru the pump, it won't look good anymore.

And speaking of doing extra work, take off the impeller. Merc specifies yearly removal and regrease the splines. Nut is tight- 150ft-lbs plus corrosion. The wear ring should be bolted in place. It prevents excess side movement as you pull on the wrench. Need special socket from Merc. Maybe a box end would work. There are 2 flats on the shaft ahead of the impeller for an open-end wrench. Easiest with 2 people. Don't damge that shaft end. It is both bearing and seal surface.

A little epoxy resin painted inside the wear ring can help restore what is worn.

 

[pgilchri]

Thanks for the tips Tim. I like the way you think, I too would prefer to take care of things now, but I ended up reassembling everything today as my family wants to go out this weekend. I have no local source for parts and Mercury seems to be running out of certain items like the large anode on the rear. Anyway, I did order new bushings and a new seal for the stator and will replace it the next time I service it. I’ll also take your advice and loosen the impeller but next time too. For reassembly I used silicone grease on all the mating services to help ensure it went together smoothly and sealed. Everything went well. Hopefully somehow things will be fixed, but I’m not sure what to expect.


On a related note, what is the deal with the grate design? Why is it hinged to open upward? I can’t figure it out.


Thanks,
Patrick

 

[Tim75]

Thanks for the tips Tim. I like the way you think, I too would prefer to take care of things now, but I ended up reassembling everything today as my family wants to go out this weekend. I have no local source for parts and Mercury seems to be running out of certain items like the large anode on the rear. Anyway, I did order new bushings and a new seal for the stator and will replace it the next time I service it. I’ll also take your advice and loosen the impeller but next time too. For reassembly I used silicone grease on all the mating services to help ensure it went together smoothly and sealed. Everything went well. Hopefully somehow things will be fixed, but I’m not sure what to expect.


On a related note, what is the deal with the grate design? Why is it hinged to open upward? I can’t figure it out.


Thanks,
Patrick

It was to release weeds caught in inake.

 

[pgilchri]

Well a quick update. We finally made it back out on the lake it didnt seem like much had changed. With just my wife and I plus a small cooler we hit 37 at wot on a glass lake. Still not sure why I seem on the slow side. Could it be my elevation (2300ft?) That's my best guess at this point.

 

[pgilchri]

Just did some googling and found this article. What a Drag! How to Add Pep to Your Boat for High Altitude Performance | BetterBoat Boating Blog

Makes me think elevation is my problem.

On a related note, would trim tabs help get me on plane when fully loaded?

 

[Dr Honda]

2300' isn't that high honestly. I'm at 1500' or so... and if it's just me and one other person.... with a cooler, and a full water tank... and the top up... I'm doing 45 without too many issues. What RPM are you getting to?

 

[pgilchri]

5900 rpm at wot

could the bucket be dragging? Is there a procedure for aligning the bucket in forward?

 

[rldavis]

5900 doesn't seam like WOT. Does the engine begin to rev immediately when you move throttle lever or do you have to move the lever a bit before you get RPM change? It could be your throttle cable is in need of adjustment. Also I have heard of a learner key do you have two keys?

 

[pgilchri]

I was under the belief that 5900 was right in spec.

 

[rldavis]

5900 doesn't seam like WOT. Does the engine begin to rev immediately when you move throttle lever or do you have to move the lever a bit before you get RPM change? It could be your throttle cable is in need of adjustment. Also I have heard of a learner key do you have two keys?

Yes you are correct 5900 is max RPM

 

[rldavis]

Yes you are correct 5900 is max RPM

Did you make sure that the part number on the impeller is correct for your boat?