Utopia only doing 41 mph

[jasguild]

This weekend the water it was relatively calm so I decided to see how fast my utopia is running WOT. I had 2 adults and 2 kids a full tank of gas and regular gearsTo my disappointment I only got 41 mph using seatow software on my phone. My speedometer on the boat registered 47 mph but I dont believe that.

I changed my oil and plugs as well as the temp sensor on the port side of engine at the start of the year.

I have 250 hours on the boat and I got a compression test last year that registered 130 in each cylinder.

Could this be cavitation issues? Any other suggestions?

 

[Dr Honda]

Since I don't know what Utopia you have, or what engine... or really how much weight you had in the boat... it's hard to say how fast it should have been running.

Oh... also... if you have a Bimini top on... they can scrub 4~6 mph off the top end.

If you have "Cavitation"... the you will have a hard time accelerating. If it's bad enough... the engine will bounce off the rev-limiter, and you won't go anywhere. But... if you have excessive wear in the pump... or light damage to the impeller... that will scrub speed too.

Lastly... where you bouncing at all? If you were... you could have moved the people around, to see if you could have run flatter. That's important to find that last 3~4 mph. That's why a lot of people will add trim tabs.



Anyway... 41 mph isn't bad... but I'm sure there is some room for improvement.



****EDIT****


I just did a little digging around... and it looks like the Utopia 185 with a 210 Merc runs 45 MPH. The Utopia 205 with the 240 merc runs 47 mph.

I'm sure the speeds posted above were with one person. So... a normal load, and some time on the drive... 41 sounds right to me.

 

[jasguild]

Since I don't know what Utopia you have, or what engine... or really how much weight you had in the boat... it's hard to say how fast it should have been running.

Oh... also... if you have a Bimini top on... they can scrub 4~6 mph off the top end.

If you have "Cavitation"... the you will have a hard time accelerating. If it's bad enough... the engine will bounce off the rev-limiter, and you won't go anywhere. But... if you have excessive wear in the pump... or light damage to the impeller... that will scrub speed too.

Lastly... where you bouncing at all? If you were... you could have moved the people around, to see if you could have run flatter. That's important to find that last 3~4 mph. That's why a lot of people will add trim tabs.



Anyway... 41 mph isn't bad... but I'm sure there is some room for improvement.



****EDIT****


I just did a little digging around... and it looks like the Utopia 185 with a 210 Merc runs 45 MPH. The Utopia 205 with the 240 merc runs 47 mph.

I'm sure the speeds posted above were with one person. So... a normal load, and some time on the drive... 41 sounds right to me.

Sorry about the incomplete information. I have a utopia 205 with the 240 hp model and I did have the bimini down. It was doing the "dolphining" quite a bit.

The truth is I much prefer a leisurely drive at 25-30 mph but was concerned that I have a repair bill staring me in the face.

Thanks again for your response. I feel somewhat better.

Sincerely

 

[Dr Honda]

I would say you are fine. If you would have moved the kids to the front of the boat... You would have found another 3~4 MPH... and that's close to the posted speed.

Assuming your engine is getting right to 6000 RPM at full throttle... if you cleaned up your pump and impeller... that would also get you those last few MPH. But... since you are like most people... and not really running wide open... I'd say it's a lot of work and $$$ to get back a small amount of performance.

I just noticed you are in FL. if it was hot and humid... you would have lost a little speed from lower HP.


Since your compression is good, and it sound's like you don't really have a mechanical complaint... I'd say not to worry. I'm sure there is nothing wrong.

 

[Seadoobuddy]

I would say you are fine. .......
I just noticed you are in FL. if it was hot and humid... you would have lost a little speed from lower HP.

Why does hot/humid decrease speed/HP?

 

[Coastiejoe]

Why does hot/humid decrease speed/HP?

Hot air is thinner than cold air. Thus , you literally get less air into the combustion chamber.

It is a more dense less dense thing.

 

[Racereddie]

Sorry about the incomplete information. I have a utopia 205 with the 240 hp model and I did have the bimini down. It was doing the "dolphining" quite a bit.

The truth is I much prefer a leisurely drive at 25-30 mph but was concerned that I have a repair bill staring me in the face.

Thanks again for your response. I feel somewhat better.

Sincerely

Check this link out. http://www.boattest.com/boats/boat_video.aspx?ID=233

It is a test of a 2002 Utopia 205, my 2003 ran very close to these numbers. Look at the Test Reviews tab for the test conditions. If the video does not play you need to sign up, cost is free, just need an e-mail, you don't get spam from the web site. If all your conditions are met and you don't get 47mph GPS then KB weld on the wear ring would be the first inexpensive trick to try. There is a lot of info on the forum.

Hope this helps.

Eddie