Lost 200 rpm????

[fasttrucker]

The top rpm used to be 5400.Now its at 5200 anything to worry about.Iam thinking it could be the warm summer air.:rolleyes:

[Mr X]

Thats EXACTLY what it is. It costs me 250 RPM down here.

[fasttrucker]

Thats EXACTLY what it is. It costs me 250 RPM down here.
.......Thanks Mr.X...I was a little unhappy:banghead: ,also lost a few mph,from 75mph to 70,71,72.

[MOP]

What may also be adding to that is how much of last years gas is in the tank? On my 16 which I had for enough years noticed that by the 3rd fill up it was running better. I used StaBil but the octane drops quite a bit over the layup period.

Phil

[mrfixxall]

The top rpm used to be 5400.Now its at 5200 anything to worry about.Iam thinking it could be the warm summer air.:rolleyes:

Did you fog your engine when winterized? if so you may have a fouled plug or all the plugs ma be slightly fouled....

[Pismo]

On the contrary (possibly), this new formulated gas with 10% ethanol will give you less power. 200rpm sounds like a lot tho. You may run faster on last years gas and slow as it gets replaced with the new higher ethanol mix.

[Pismo]

From an old post..............


"The Mobil station near me has a sign on the pump saying "10% ethanol" so hopefully we'll be alright per the Mercuiser statement. Should loose a bit of hp tho, ethanol has only 72% the stored energy of straight gasoline. There has always been some ethanol in the mix, it is just a higher percentage now. So if straight gas has 100 units of energy per gallon then 10% ethanol gas will have 97.2 units or 2.8% less. This does not take into account the ethanol that was in old formula gas, so the loss should be even less, say 2.0% total. So does that mean my 75.5mph GPS best will now be 2% less down to 74.0mph GPS?......We'll see."


So 5400 minus 2.8% is 5249rpm. But there has always been ethanol is gas so this calc is a over some. 5400 minus 2% is around 5300rpm.

[LKSD]

Heat, humidity & fuel would be the first things that come to mind.. Unless you changed props or something else.. Time for a blower or Sc ?? Just kiddin' ... J

[fasttrucker]

Ive been running fresh fuel 92oct.I always seem to be faster the start of the season.:checkered I do a complete tune-up every year oil,plugs, cap,rotor,outdrive service.Iam sure its just the warm air:lightning like Mr X said.

[LKSD]

It probably is the hotter temps. I just after hearing your mini ordeal here thought it could have been the exhaust.. Hopefully we will sneak down the bay soon.. We will call ya when we do (althought I will be sure to call ya earlier than I did last time.. ) .. Jamie :)