tfarmer

Hello I am a new sonic 260 prowler496ho mag. owner. This is my first (real) boat. I took it out this weekend and When I start to give it throttle it feels like it is missing or shaking
from 1500 rpm to about 2800 and when the boat gets up on the water I cant feel any thing wrong. I got the boat to run 63/65 24 p (I dont have a gps yet). I ran the rpm to 5000 and went about a mile or so and I felt the engine try to shut down for a brief second and then it was fine for another mile or so and it started to do it alot.
If the rpm is around 3000 it wont do it. It feels like it is running out of fuel at high rpm. It looks like it has a fuel pump on the left lowerside of the enging?? And maby another pump beside the spin on fuel filter??? I need some help with this. I cant find a port to check the fuel pressure. Where is it at and how much pressure should it have? Im not sure if I have one or two problems. It does have a new fuel filter on it The compression checked out, new plugs, the engine sounds just fine at a idle. I also took out all the fuel injestors to see if there was any dirt or trash in them and they all were very clean. The boat has 196 hrs on it .Any help would be great. Thanks, Timmy.

Sydwayz

Do you have a fuel switch under the rear seat? Are you sure its in the correct position? (I had a 1999 Sonic 26' and my switch was labelled 180* opposite of being wide open.)

Did you just un-winterize? Sounds like you could have fouled a few plugs when burning out the fogged in 2-cycle oil from the fall. I'd replace all the plugs each season. Its too easy not to on a single engine boat. Double check your spark plug wires to make sure they are in the right order and all are fully connected and clicked onto the plugs. Did you change the fuel/water separator for the new season? Also a good practice. There is also an inline fuel filter, which it appears you know about. That needs to be in good order too, obviously.

Who winterized it? Was this your first weekend out with it?

Where are you located, just out of curiousity.

tfarmer

Hello and thanks for your reply. I just purchased the boat and
not sure If the marine dealer or someone else winterized it.
We are in Paducah, ky. I did new spark plugs and oil change,
checked all coils and wires, compression, new spin-on fuel filter. still no change. You said there is a inline filter where is
this? I will check just to make sure. Thanks, Timmy.
cell# 270 331-0695

GO4BROKE

Check all your electrical connections, especially the main engine harness plug, and ignition switch. Also check that new filter for water in the gas. Just drain the filter into a glass jar, the water will sit on the bottem of the jar. Don't use drinking glasses, it makes the wife mad!

Sydwayz

Timmy, its been a few years since I owned my Sonic and mine had a HP500EFI. It looks like a common in line automotive fuel filter. I have 496HOs in my current boat. Its probably mounted on a stringer in the fuel line on the way to the fuel/water separator (which is a filter too which looks like an oil filter; that you replaced). The fuel/water separator can also go bad as well (as in bad from the get go).

GOODT

The filter that brian speaks of will be between the fuel tank and the boost pump (pump next to water separator) if you do not see it then you may not have them installed,

merc came out with a service bulletin about installing these filters in either 02 or 03 I dont remember, because debries from fuel tanks was destroyng the fuel pumps, it is possible that yours never got upgraded

the srader valve is located on the front top of the motor it is kind of hiden by the resivor tank

I would check your fuel pressure both running and static, alot of times you can hear a bad pump also you can pull the pump, on on the inlet side of the pump is a screen that may be clogged if this is the case more then likly both pumps (Boost and Pressure) should b replaced

oh and if you have to replace the pressure pump my advice is pay someone to do it it is a royal pain in the as*

tfarmer

Im going to do all this and see if anything is wrong. Any more info will be great. Thanks for all your help. Timmy. Anyone know what the fuel pressure should be at wide open throttle?

islandracer

I heard in the Northeast Region that a lot of the Ehanol fuel(corn based) is showing up at the gas stations.

My mechanic indicated to me to stay away from these as the 496 HO will not work with this type of fuel.

I don't have that problem where I live... but some of you may need to be careful.

frank

tfarmer

Im sure I found the problem today. I started removing the complete fuel system flushing and cleaning every part. And all
was clean untill I took the low pressure pump apart and found
the screen plugged solid. It looks like little pieces of soter from
building the fuel tank.and a little dirt. I went ahead and cleaned the complete
fuel system and added a fuel filter. You all have been great
help thanks alot. Timmy.

GO4BROKE

Glad you found it.