Prop questiin

[Jeff Delbuono]

I just got a 98 290 sundancer with twin 5.0 efi on alpha 1 gen 2 drives. Put in water and motors will not get over 3000 rpm and will just stand up and not plane off. Changed everything ya can on motors. Ran with a seperate fuel tank. Timing and vac test. Fuel press test and compression test is all good. Now thinking it might be the props. Called sea ray and was told i am supposed to have 14.5 x 17 pitch props. Pulled the props and have 14 x 19 pitch is that my problem. Any thoughts before i spend a grand for no reason. Please help

 

[LG111]

Not sure if this is the problem... most likely it is, but who then and why did someone put 17" on in place of factory spec? If you can history that out then you'll know.

 

[CliffA]

Not sure if this is the problem... most likely it is, but who then and why did someone put 17" on in place of factory spec? If you can history that out then you'll know.

I think you read that wrong....the standard props are supposed to be 17 pitch....someone changed them to 19 pitch.....probably looking for additional top end speed but ended up lugging the engines instead....

cliff

 

[Jeff Delbuono]

Thats my thought too. I called the old owner who had it from 2000 to 2018. Told me it was the props that came with it when he got it. Boat motors gave 325 hrs so thinking he just never left the dock. Going to a prop shop today to see if they will loan me a set before i buy. Will update with results

 

[LG111]

I think you read that wrong....the standard props are supposed to be 17 pitch....someone changed them to 19 pitch.....probably looking for additional top end speed but ended up lugging the engines instead....

Thanks! I should just read when having two glasses of wine!

Cheers

cliff

 

[M Prod]

I don't think your props are the real issue here. Probably not helping, but an inch of pitch is only good for about a 200 RPM difference. If you're over propped by two inches, then you should still be able to get up to 4000-4200 RPM minimum with those engines. Your diameter on the new prop is also down a half an inch from spec, so this subtracts 100RPM from the equation. Those props should only be bringing the engines down by 300RPM from recommended WOT ...if it were just the props. Hard to say what the issue is, but it sounds like more than just props.

 

[CliffA]

I don't think your props are the real issue here. Probably not helping, but an inch of pitch is only good for about a 200 RPM difference. If you're over propped by two inches, then you should still be able to get up to 4000-4200 RPM minimum with those engines. Your diameter on the new prop is also down a half an inch from spec, so this subtracts 100RPM from the equation. Those props should only be bringing the engines down by 300RPM from recommended WOT ...if it were just the props. Hard to say what the issue is, but it sounds like more than just props.

I believe on this particular boat two inches of pitch will make a significant difference....the 290 is a heavy boat and when it is fully loaded with fluids, stuff and people the 5.0's might be marginal as far as power is concerned, especially with Alpha drives....the only way to find out is put the correct props on and test the performance.....

also if one engine is not running 100% then it can cause the other engine to not hit WOT rpm range as well because it is not strong enough to make up the difference in power the other engine is loosing.....

cliff

 

[Drwikboz]

200 rpm per pitch. Having same issue now, installed 4 blades this year, lost around 400-600 rpm.

Gonna go down 2 pitch and see what happens.

Also, see if you can get a computer on it, maybe something else is putting the motors into limp mode. Probably not since it is both but you never know.

 

[Jeff Delbuono]

So finally figured my issue. After having props re pitched. Spending countless hours and money on a mechanic i finally fired him and got a merc mechanic. He fixes it in an hour. Timing issue amd wires out of firing order

 

[NorCal Boater]

Very glad you got it figured out Jeff and glad it was something simple. Sometimes that 2nd opinion makes all the difference.

Happy boating....

 

[M Prod]

Fantastic. Glad it wasn't too complicated. I went through the prop madness last year, only to finally come to realize my problem was in the engine as stated above. Glad you were able to mostly avoid that.

Anyway thanks for the follow up, and +1 on safe and happy boating.

 

[Black Valkyrie]

Fantastic. Glad it wasn't too complicated. I went through the prop madness last year, only to finally come to realize my problem was in the engine as stated above. Glad you were able to mostly avoid that.

Anyway thanks for the follow up, and +1 on safe and happy boating.

Osborne props is helpful

 

[M Prod]

Osborne props is helpful

Not when the problem isn't the props.

 

[Jeff Delbuono]

It comes down to if you cant fix it yourself get a merc mechanic to fix it. A car mechanic is good for your car but knows nothing about boats