Prop questiin

Jeff Delbuono

Well-Known Member
Jun 11, 2018
1,125
Edison New Jersey
Boat Info
1998 Sea Ray 290 Sundancer
Engines
5.0 efi w/ alpha 1 gen 2 drives
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
 
I doubt 2” pitch will make that much difference, but a good prop shop might have some loaners before you buy.

I had a boat that had similar issues, but they had varnish in the carbs that worked fine after a couple cans of carb cleaner.

With that said, my old 5.7 had an acceleration jet, might the EFIs have a similar syste?. I’m thinking the efi system is the issue.
 
Although there can be performance differences, I agree with the guys above that it's not "the" issue. A dirty bottom can do it, though. Plugs? Are you new to boating? Are you trimming all the way down? Have you physically verified that the drives go all the way down?

What does the previous owner say? Did it do this on your test ride?
 
Boating 18 years and #5 boat. Boat sat for 7 years on blocks so never got it on water for test ride.
Twin 5.0 efi on alpha 1 gen 2 drives

(Already changed on both motors)
New plugs, wirs, cap, rotor, coil, fuel injectors, fuel seperators, fuel pumps, igniton moduel, map sensor, knock sensor, balancers

Vac test, fuel pressure test, compression test all good. Ran on a seperate fuel tank and same results. Only thing i can come up with is now the props
 
Called the old owner. Said it was the props he got it with in 2000. Stated he did not change them
 
How bout doing a leak down test? A compression test is "OK", but a leak down test is much more conclusive. If for nothing else, it "should" eliminate engine power issues as a variable. The 17's will help, that's just science, but you should have enough power to get going with 19's. Meaning, if the reason you can't get on plane is because of the 19's, then something else is going on (engine power, for example).

Physically verified drives going fully down? Any differene when using tabs?
 
On all tests drives were all the way down. I was told by my local prop shop that i am def over propped. If specs call for 14.5 x 17 that is correct. Boat is approx 13,000 lbs with twin 5.0 efi. Already under powered with the weight of the boat. 19 will not let it get over the hump to plane off. Gonna give it a shot tomorrow and see.
 
I've run that boat with those engines, but only with B3 drives - so not exactly apples to apples. Get some more data with the 17's and that will help solve the mystery. Get top end speed with a light load, trimmed up as much as it will take. Note the MAX RPM, as well.

Tabs?

A question that arises, though, is why did the PO have the 19's on there for as long as he did if it wouldn't get on plane?
 
I agree. Good question. Only things i can think is the first owner put them on. He kept it on the hudson in nyc and never really left the dock. Or what im thinking is when i got the boat i pulled.the drives and took to my marina to have them serviced and new skegs welded on. Im thinking they put the wrong props on due to them being super busy and completly unorginized.
 
I agree. Good question. Only things i can think is the first owner put them on. He kept it on the hudson in nyc and never really left the dock. Or what im thinking is when i got the boat i pulled.the drives and took to my marina to have them serviced and new skegs welded on. Im thinking they put the wrong props on due to them being super busy and completly unorginized.
 
our 98 290 has alphas and 5.7efi's but came from the factory with the 19's and never had a problem with them. it actually hit 4800 WOT and we have the genset as well. I know not apples to apples but the 350's don't make that much more power. We run 4 blade 14x20 aluminum now and get 4600. The 4.3's even came with 13.75x21 SS 3 blades

I think something else is of here. It's also weird that your combination of engine/drive isn't listed on the original prop sheet (attached) although I've seen plenty of 98's with the 305's

Longshot, but are the lower's original? Maybe if they were swapped someone messed with gear ratios. They should be 1.47:1
 

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