2004 doral 255 monticello problem

[boots89]

I just purchased the boat and I'm having some issues. The boat is having a hell of a time planning out, especially when I have multiple people on the boat. The lower unit was replaced due to an accident by the previous owner and I'm thinking the wrong props were installed or possibly the diesel props were installed. The lower unit says Volvo type dp-sm1, ratio 95. The props say f7rear 3851477 9j, f7 front 3851467 9j. the boat is 8.5 ft beam, 25ft in length not including swim platform. The engine is the volvo 350 mag. Any info on what props should be on it would be great, thanks.

 

[Maclin]

Re: 2004 doral 255 monticello problem

F7 props are not for diesels, but they are pretty tall pitch for that big of a boat. Usually 22 footers have F7's while larger boats would have F5' or F4's even depending on the largess.

Those are generalities, you might poke ariound on the web and see what other 25 foot Dorals like yours or even other model boats have regarding Volvo Penta DuoProps. Your best bet would be a Doral club board, I bet there would be a lot of help there regarding finding out what it might have been shipped with OEM.

Can you give us what the top RPM and MPH you can hit now? Also what condition you think the engine is in, a good state of tune, still good compression, good drivability except for the sluggihs planing. Once it planes out does the engine respond and rev higher? Observations like that would help.

 

[QC]

Re: 2004 doral 255 monticello problem

Can you give us what the top RPM and MPH you can hit now?

Yeah, and speed preferable by GPS. This is where to start. I would even say it doesn't matter what it was shipped with as that may suck too depending on what load etc. Altitude?

 

[boots89]

Re: 2004 doral 255 monticello problem

F7 props are not for diesels, but they are pretty tall pitch for that big of a boat. Usually 22 footers have F7's while larger boats would have F5' or F4's even depending on the largess.

Those are generalities, you might poke ariound on the web and see what other 25 foot Dorals like yours or even other model boats have regarding Volvo Penta DuoProps. Your best bet would be a Doral club board, I bet there would be a lot of help there regarding finding out what it might have been shipped with OEM.

Can you give us what the top RPM and MPH you can hit now? Also what condition you think the engine is in, a good state of tune, still good compression, good drivability except for the sluggihs planing. Once it planes out does the engine respond and rev higher? Observations like that would help.

Yeah, and speed preferable by GPS. This is where to start. I would even say it doesn't matter what it was shipped with as that may suck too depending on what load etc. Altitude?

Thanks for the response, if I remember correctly I had it full throttle around 4500rpm maybe a little more and the boat was running 40-41mph going by the gps. The boat is top shape has around 180hrs on it, all the service work has been kept up on it. When they installed the new lower unit I believe they installed different props which are wrong. Once it's cruising it goes ok, still sluggish. So I'm thinking like you said a F5 might be the way to go.