04 Chaparral signature 240 low power when cold and missing

[Beech2000]

Our neighborhood friends have an 2004 Chaparral 240 that recently developed low power and bumping feel at first running of the day. Vessel now has 305 hours.

We have been waiting to throttle her up until we see 130 to 150 on temp and same thing no power and bumping feel during accell. Once she's warm soaked all is good even though no difference on temp gauge.

Here is what has been done by Marine Max to date:

Distributor Cap and Rotor change out.
Wires check good. (Not sure how they verified this)
Plugs have 10 hours and check good.
Coil not checked
Fuel Filter / Water Sep. change out.
Fuel pressure checked.
Fuel injection tested. (Not sure of details)

They recommend a compression check but bill was getting to high and they didn't sound like they wanted to mess with it anymore.

Engine is Mercrusier 5.7 EFI with Bravo 3

Idea's folks?

[redtech]

does this bumping feel like it's in the drive or a miss in the engine
if in the drive the bravo 3 uses a cone clutch and i have had these bump or thump into gear

[Beech2000]

Originally Posted by redtech

does this bumping feel like it's in the drive or a miss in the engine
if in the drive the bravo 3 uses a cone clutch and i have had these bump or thump into gear

Hard to say. Feels like ignition but suspect its some sensor gone bad with the fuel injection due to the reduced power. Is the EFI system pretty easy to troubleshoot?

[redtech]

fuel injection is pretty easy to trouble shoot if you have the tools or at least a book
if there is no check engine light on then there is no hard codes in the computer
from my experience this is just a starting point you still need a scan tool to see what codes are in the computer if there are any
starting with the basics are the best and not replacing components but finding the bad one is cheaper in the long run plus you will get a better understanding of fuel injection
take a look at the shift interupt switch
best of luck to you

[Beech2000]

Originally Posted by redtech

fuel injection is pretty easy to trouble shoot if you have the tools or at least a book
if there is no check engine light on then there is no hard codes in the computer
from my experience this is just a starting point you still need a scan tool to see what codes are in the computer if there are any
starting with the basics are the best and not replacing components but finding the bad one is cheaper in the long run plus you will get a better understanding of fuel injection
take a look at the shift interupt switch
best of luck to you

Is the scan tool the same as OBD standard used in cars for mercruiser EFI?

[redtech]

yes it is just a differant cartridge
i use a laptop program but a otc 2000 works to

[Beech2000]

Originally Posted by redtech

yes it is just a differant cartridge
i use a laptop program but a otc 2000 works to

Cartridge? you mean connector?

I have an OBC 2 scanner for automotive. Mercruiser EFI engines use there own diagnostic scanner?

Where does it plug into? Where and how much is the scan tool?

[Beech2000]

All, FYI. The problem was a .40cent sponge filter in the throat of the throttle body that was plugged.UGH!