No power

[Cadeco]

Two weeks ago i went to the water w/ 7 people (total) and something did happen: My Islander has a F250 Yamaha ( of course 4 stroke) and With throttle down, around 5000/5200 RPMs I could not pass over 14/15 MPH., I called the mechanic and explain the issue, He told me that it should be a problem w/ the Hub on the propeller. I removed it and took to a propeller place to change the hub, today i got a call they told me that after putting pressure the HUB ( I guess this is how is called that rubber thing inside the propeller) It did not move and their opinion is that the hub is ok! What do you guys think about it? I don't think that 7 people would cause that problem, so, I will ask you guys for help. Has anyone had the same problem?
Thanks for all the incoming responses.

 

[seasick]

When you tried to accelerate did the revs go up quickly or did they struggle to increase? Could you have gone more than 5200 revs or was that as fast as the engine would rev to?
I assume that the boat never got on plane. Is that true?
Is the hull relatively clean?

 

[wspitler]

If your tachometer is correct, there are only three possibilities. Cavitation, a slipping propeller hub, or major gear case failure. You should be able to hear and feel cavitation and gear failure.

 

[DennisG01]

-- Dirty bottom
-- Cavitation (highly unlikely unless the prop is damaged)
-- Ventilation... can be caused by numerous things, even just some weeds on the prop
-- Weak hub (seems like that may not be it)
-- Mechanical problem
-- Trailer still attached

 

[seasick]

If it were a spun prop or a somehow slipping gear box, I would expect the motor to be able to rev higher. The fact that is revs up to 5200 and stops also tells me the prop is not experiencing a high slip rate.
It sounds like the combo of boat, motor and prop is out of horse power. The prop could have lost its cupping but I think that would have been obvious to the prop shop.
So either the boat never could carry 7 people or there is lot of drag. OR...
I had also asked if the boat got on plane. If it did it was going faster than 15 mph
If the speed was noted using the dash gauges and not GPS, I would suspect that the pitot sensor tubs is plugged.

 

[Halfhitch]

-- Dirty bottom
-- Cavitation (highly unlikely unless the prop is damaged)
-- Ventilation... can be caused by numerous things, even just some weeds on the prop
-- Weak hub (seems like that may not be it)
-- Mechanical problem
-- Trailer still attached

https://globalnews.ca/news/6977146/boat-with-trailer-bc-lake/

 

[Cadeco]

Ok Guys.
First, thanks for the interest.
Second. The revs did not stop at 5000 rpms and did not struggled to increase but if i tried to go over, the whistle would come on ( I tried twice and had to turn the throttle back). There were no weeds or anything else on the propeller, as well as the trailer was not "still attached" (that was really a good one). I can't believe that the boat should have had a problem w/ 7 people on board., even knowing (now i know) that an Islander 268 w/ a F250 is a bit underpowered.
Any ideas?

PS: Tanks to all of you for trying to help.

 

[Mustang65fbk]

Your Islander sounds like it could be very much underpowered with a single F250 on it and with 7 people on board. I'm thinking that most of them likely came with twin 200's as the maximum horsepower rating for the boat, depending on which year you have, is 400 hp. You could very easily determine if the boat was struggling to get on a plane with the added weight simply by going out by yourself and seeing if she still struggles to get up on a plane.

 

[Cadeco]

Your Islander sounds like it could be very much underpowered with a single F250 on it and with 7 people on board. I'm thinking that most of them likely came with twin 200's as the maximum horsepower rating for the boat, depending on which year you have, is 400 hp. You could very easily determine if the boat was struggling to get on a plane with the added weight simply by going out by yourself and seeing if she still struggles to get up on a plane.

That's what my mechanic told me to do. I will do it. but anyway I will try to sell my motor and get twins 150/175/200 - all depending on weight.
Thanks.

 

[SkunkBoat]

Are your tabs stuck all the way down?

bottom covered in barnacles?

 

[Mustang65fbk]

That's what my mechanic told me to do. I will do it. but anyway I will try to sell my motor and get twins 150/175/200 - all depending on weight.
Thanks.

I'd honestly look at a single Suzuki 350 for a multitude of different reasons. First of all, your boat is already rigged for a single main motor, which you could keep it that way with a new single Suzuki 350. Also, you're likely going to spend half the money, or maybe even less, buying a single outboard as opposed to buying twin outboards. Lastly, the weight savings of having a single larger main motor as opposed to having twin main motors will be noticed quite a bit. The Suzuki 350 outboard weighs 727 lbs, comparatively twin Suzuki 150's would be 1,060 lbs total. Twin Yamaha F150's will also be over 1k lbs, same with twin Honda 150's and even the lightest 4 strokes which would be Mercury's are still going to be near 1k lbs. You'd be saving about 250 lbs of weight in the stern with a single outboard and you'll save a good deal of money as opposed to buying two main motors. I know that Mercury also makes a single 350/400 hp outboard and they're slightly less weight, but they are typically more expensive than the Suzuki's. Neither Honda nor Yamaha make anything between the 300 hp level and the 400 hp level, though Yamaha does make an F425 but that is more horsepower than your hull is rated for and it weighs almost 1k lbs as well. Just my opinions though, good luck!

 

[hooked on Grady]

definitely go with single 350 as mentioned above imo. I feel like my old 225 on the 24 was under powered with 2 big gas tanks and beefy hard top. so only 25 more hp on that rig with a full load makes sense

 

[glacierbaze]

I can’t think of seven people that I would want to take out on my boat, especially at one time. But if I did, it would be rarely, and for short periods, and I would try a lower pitch propeller before I spent the money for a re-power. Assuming that 250 does well enough for 3 or 4 people.

 

[DennisG01]

One thing you didn't mention (and I suppose I assumed you were doing it correctly since you probably have had the boat for a while?) is how you had the engine trimmed and whether or not you used tabs.

Run it again with just you - or just a couple people - see how it does.

While 7 people can certainly make a difference, it shouldn't be to the extent that you can't even get up on plane.

 

[Mustang65fbk]

definitely go with single 350 as mentioned above imo. I feel like my old 225 on the 24 was under powered with 2 big gas tanks and beefy hard top. so only 25 more hp on that rig with a full load makes sense

Someone actually agreed with me.... always a first time for everything

On a serious note though and to the OP, I'd repost this in the general discussion part of the forum as you're going to get a lot more traffic and likely a few more answers or opinions there.

 

[kirk a]

How does the boat perform with just one or two folks on board???

I know that on my 330, things are sluggish when fully loaded for a canyon trip. The extra 4K lbs makes a huge difference.

5 extra people at 200 give or take is another 1000 lbs before their gear is taken into account. On a marginally underpowered boat that is going to be a big difference

 

[seasick]

The whistle you mentioned when going over 5000 revs is probably an alarm. That is something to look into. My first thought was an over rev condition but that shouldn't occur at 5000 or 5200 revs.
On another note, I did wonder if trim tabs were deployed but figured that was checked.
I agree that you probably are under powered for the load but that doesn't explain the alarm.

 

[Mustang65fbk]

I've also had something similar to where I believe it was ultimately an issue of bad gas, and no not the kind of bad gas you get after eating Mexican food, but a couple times using different boat for the first time of the season after sitting all winter you'd try getting up on a plane and it would over-rev and you wouldn't have the normal level of power. After trolling around for a bit and going through a little bit of gas and trying it after that, then the problem would go away. Any possibility you have bad or untreated gas that hasn't been used for some time? Maybe not as big of an issue in Florida, but here in the Seattle area where boats sit for 6-7 months or more it can definitely be an issue.

 

[Fixit]

What make model diameter and pitch of prop?
Is it a pressed in rubber hub or a plastic square one? I’m still suspect of a bad rubber hub. Do you have a prop you can borrow to test out?
What’s your wot rpm and speed normally?
My 270 islander won’t plane on a single 200hp Yamaha with a 17” pitch sws prop 15-3/4” diameter. With 7 people you might be under pitched did you try “everyone come up front to the bow”

 

[Cadeco]

What make model diameter and pitch of prop?
Is it a pressed in rubber hub or a plastic square one? I’m still suspect of a bad rubber hub. Do you have a prop you can borrow to test out?
What’s your wot rpm and speed normally?
My 270 islander won’t plane on a single 200hp Yamaha with a 17” pitch sws prop 15-3/4” diameter. With 7 people you might be under pitched did you try “everyone come up front to the bow”

Yamaha 17-M - No I did not try everyone one the bow