help - lost top end

bluefox70 · 08-22-2009, 07:50 PM

Hello All,

I have an '04 25 outlaw with the 425hp. It has a 23P balanced prop and captains call exhuast. The boat has 180 fairly easy hours on her. Last summer it was doing 66-67mph on gps at 5200rpms. This summer I am getting about 62mph at 5000rpm's.
It idles fantastically at 700 and cruises at 3800 45mph dead on with 2 people 1/2 tank of gas.

So, what happened? I changed my water/fuel seperator and in-line fuel filter, which by the way I got screwed for $52.
I am not sure of the next step, the prop looks great and I am looking for advice. Oil is changed every 20 hours.

Cheers,
Scot

Irishtornado · 08-22-2009, 09:02 PM

Quote:

Originally Posted by bluefox70

Hello All,

I have an '04 25 outlaw with the 425hp. It has a 23P balanced prop and captains call exhuast. The boat has 180 fairly easy hours on her. Last summer it was doing 66-67mph on gps at 5200rpms. This summer I am getting about 62mph at 5000rpm's.
It idles fantastically at 700 and cruises at 3800 45mph dead on with 2 people 1/2 tank of gas.

So, what happened? I changed my water/fuel seperator and in-line fuel filter, which by the way I got screwed for $52.
I am not sure of the next step, the prop looks great and I am looking for advice. Oil is changed every 20 hours.

Cheers,
Scot

Change your plugs...

Was the temp and humidity the same? Heat will cause loss of speed

indywhsle · 08-22-2009, 09:57 PM

you also may want to check the compression to be safe.

TEAMBAJA · 08-22-2009, 10:27 PM

Quote:

Originally Posted by irishtornado

Change your plugs...

Was the temp and humidity the same? Heat will cause loss of speed

At the last dealer meeting every boat was about 4 to 5 mph slower in the Florida heat. Up here they ran fine.

bluefox70 · 08-23-2009, 08:55 AM

Interesting, I am in New Hampshire and our humidity over the last week has been horrendous and temps around 90.

These are platinum $$$ plugs, how often would you change them?

Cheers

Irishtornado · 08-23-2009, 09:51 AM

Quote:

Originally Posted by bluefox70

Interesting, I am in New Hampshire and our humidity over the last week has been horrendous and temps around 90.

These are platinum $$$ plugs, how often would you change them?

Cheers

If they are the original plugs I'd probably say your due...

relaxalot · 08-24-2009, 12:44 PM

Motors vary wildly due to heat. My boat runs up to 8mph difference in 115 degrees versus 80 degrees.

redbud35 · 08-24-2009, 08:47 PM

My bet is the heat and water temp.

bluefox70 · 08-25-2009, 12:47 PM

The boat has a closed system. So, its not water temp. Heat and a mixture of moisture makes sense, though.

I have done the in-line fuel filter and water seperator with no luck. I am going to do the plugs this weekend and will update all.

Relaxalot, be happy your boat or yourself runs at all at 115 degrees. I though you had to get to New Dehli, India to see those temps.

PURPLE HORNET · 08-25-2009, 01:35 PM

It might have something to due with all this crappy gas we have been getting for awhile. I had to go up a jet size in my carb this year must be that ethanol or whatever else the gas companies are skimping on. And this year if my boat sits for 3 weeks 9 out of 10 times the front float is stuck closed.