2004 275 Pro XL Help???

[ttocs258]

Hello everyone, I am new to this site and to stratos boats so please forgive me.

I have a 2004 275 Pro XL with a Merc 115 ELPTO and a Mercury Marine Trophy Plus 4 blade stainless prop. The numbers on the prop are:48-825932A46 19P.
I have a couple of problems, first when I am on plane and WOT when I start to trim the motor up it seems like the motor starts to miss and it violentlty shakes the motor. When I trim back down it is fine. When I first got the boat it did it after being trimmed a 1/4 of the way up, now I can trim it up a little furhter with out it happening but it is still a concern. It also will not throw any roost and I am not sure if this is normal? My old bass boat would throw a massive roost and never missed when trimmed up?

My next question is after 1800 RPM my boat will take off like a streak, but from idle until 1800 RPM it is a slug. If I go from idle to WOT it will just about kill the motor. And when I try loading it on the trailer and try giving it gas it will almost always kill if I dont keep feathering the throttle back and fourth. I have replaced the plugs twice, fuel filter, drained all the gas when I first got it and ran double the dose of mercury quickleen through every tank of gas.

Some people have told me my motor sits to high on the boat, I will try to attach a photo of it.

Any help would be appreciated!!

Motor S/N: OT903 669






Modified by ttocs258 at 8:32 PM 7/30/2009

[Todd Morgan]

You are 1 hole too high.

The 115 ELPTO has a max rpm of 5250...my guess is that you're blowing past that with a 19. It generally requires a 22-24 to hold one to 5250.

Your engine uses carbs with accelerator pumps. It also only runs on 2 cylinders of the 4 until 1800 rpms.

They are a pretty durable motor.....but have some pain in the rear stuff about them. Just be glad it's not on a pontoon.

[ttocs258]

OK great!! Thank you for the info!

I guess my next question is how is the best way to lower the motor, any tricks I need to know about or anything to look out for?

Is there any way it can be bypassed so it is always running on all the cylinders instead of just two?

Thanks again!!

[Todd Morgan]

2 strong buddies and floor jack is an easy way. Let them hold it side to side while the floor jack lowers it 3/4".

No way I know of to change the 2+2 system on the 115. Doesn't mean it cant be done tho.

[ttocs258]

OK, lowerd the motor one hole (3/4") It worked much much better. Can I drop another hole or should I just leave it alone? Is there any negatives of having the motor too low?

Thanks again, when its time to upgrade from my 275 I may have to think of making trip down from wisconsin!

[BassThumb]

I was also wondering why my motor doesn't throw up a rooster tail. Its a 90 Johnson on the same boat. I figured not enough HP.

I just got the boat and it came with was a 3 blade, 12 3/4", 21 pitch prop and it would top out at about 5200 rpm when I brought the trim to the top of the trim gauge. Otherwise, top speed was at 3/4 trim and 5050 rpm and 46mph (speedo).

Now I have a 4 blade, 12 1/2", 19 pitch prop and it tops out at 5000 rpm but still 46mph, and it planes at a slightly lower speed and rpm and I like that.


I have my motor in the 3rd hole from the bottom out of 4. It appears it came from the factory dealer like that.