engine size for Sea Ray 290

[brooksk]

Hello folks,

I was wondering if anyone out there had any experience with the 4.3L LX Mercruiser engines? I am seriously considering purchase of a 1996 Sea Ray 290 DA w/ 4.3L LX twin engines. My concern is would engines of this size have enough hp and torque to get the boat moving 'adequately' or would they be underpowered for the weight / size of the boat? The boat measures ~31 OAL, has a 9' 8" beam and weighs in at 7700 lbs. I am concerned about the motor size because I believe the rating (as gleaned from the Sea Ray archives) places these motors at ~ 185hp each. I am not sure what kind of gas aspirator they have, e.g. carburetor or FI, and if carb'd not sure if there's two or four barrels on each. The 4.3L L4 configuration which was used on a few models such as the 1988 Sea Ray 270 DA looked pretty ideal to me for the hp / boat size + weight ratio. Not sure if the 4.3L LX would have as much performance. I plan on carrying mainly two adults and one 6th grader 80% but want to bring groups of 5 or 6 six other out with me on occasion, plus supplies and groceries for any overnighter's weekend sleepovers.

Kevin
Lake Champlain, VT

 

[rallyart]

Sorry, I don't have any experience with that set up, but 370 hp seems inadequate for a boat with a dry weight of 7700#
Your fuel mileage would even be better with V8's

 

[smokeonthewater]

disagree... that boat would run great with 4.3's
My wellcraft is 33' overall... 11 feet wide and 1000 lbs more dry weight.... with 260's it runs 48 mph but is a bit tail heavy at low speed... I have often thought it would be better with 4.3's and 4 blade props for everything except top speed.... Prolly still do 40 plus but be lighter in the rear and use less fuel at cruise

for comparison, on top of dry weight my boat has a cast iron onan generator from the 60's 4 group 31 batts. and holds 115 gallons of fuel and 60 gallons of water along with way too much gear....

I once had a disabled 900 cc jetski (500+ lbs) strapped on the swim platform with two buddies (another 400 lbs) holding it steady me driving (250 lbs) and one more guy in the cabin (190 lbs) and was still able to (barely) get on plane and cruise normally at 30 mph....


With the right props you would be very happy w that setup as long as you aren't worried about top speed

 

[brooksk]

Thanks for the replies. I am not concerned about setting any top end speed records using a boat of this size / type. I just want to be able to get up on plane reasonably quick so I don't waste fuel plowing the water. If my cruising speed is high 20's - low 30's mph I would be satisfied. I am not sure of the prop configuration but interested in the 4-blade prop idea. If not already, would switching to a 4-blade prop require any other hardware adjustment in the motor / lower end? Lastly, boat does have trim tabs.

 

[Scott Danforth]

if your considering the purchase, take the boat out for a sea trial and answer your own question.

IMHO, the boat will be fine with the twin 4.3's. Cruise in the upper 30's, WOT in the low to mid 40's.

Would I want more power - yes. then again, that is my stance on everything.

 

[Triangleboater]

I have first hand experience with the boat in discussion. it has the 4.3's. In my opinion you will wish you had more ponies often. Now if it's just you and a buddy going out and you don't have equipment to overnight and you aren't beer drinkers, you will be happy. But load it with 6 people and a couple coolers of beer and full gas and water, you will have a hard time getting on plane. Will it, yes but you will have to shift some weight and manage things closely.
Just my .02 cents. His boat is the 2001 sea ray 28 with the EFI 4.3's which may even have more power than what you are considering.

 

[jester31]

IMO, and with what you want to do with the boat, you don't have enough power! I figure it will plow most of the time, not get up on plane. If you had the higher performance FI or 4bbl 4.3, and 4, or 5 blade props, it might be acceptable?

 

[smokeonthewater]

Triangle, I would STRONGLY suggest that your buddy change his props... less pitch and 4 blade if he doesn't already have em Makes an absolutely HUGE difference..... When you dramatically change the weight of load in any boat you change the prop needs.... He is propped for a minimal load and struggles with a heavy one.... If he props for the heavy load he may need to watch rpm when lightly loaded so as to not over rev but his boat will perform MUCH better when he brings the troops and gear along.

I recently went through this same debate with a buddy who had a single 330 hp 454 in his sundancer.... It was a pig and would just barely get on plane with 5 people aboard and he was gonna sell it... I tried for a couple weeks to convince him to buy a prop but he was convinced that he didn't have enough motor... Finally I picked up a 16" diameter x 16" pitch 4 blade prop and brought it over...... I convinced him to take a ride and it was a whole new boat... It would jump on plane almost instantly with the 2 of us and even w 7 on board and pulling two tubes it planed out very quickly.

One of the most common mistakes in boat 'performance' is too much prop.

O/P take it for a ride before buying..... If it performs well lightly loaded you can always prop down a little IF needed for a heavier load understanding you will likely lose 2-5 mph on the top end depending on how much you change the prop though you MIGHT not lose anything if it is badly overpropped

 

[Scott Danforth]

^+1....What he said

 

[Thalasso]

4.3's (185hp).30ft boat. Those motors are going to struggle. Any more then two people on that boat it is going to struggle to get on plane. I have a 30ft'r with twin 5.0's 270hp each and i think its just right for the boat.

 

[smokeonthewater]

Thanks for the replies. I am not concerned about setting any top end speed records using a boat of this size / type. I just want to be able to get up on plane reasonably quick so I don't waste fuel plowing the water. If my cruising speed is high 20's - low 30's mph I would be satisfied. I am not sure of the prop configuration but interested in the 4-blade prop idea. If not already, would switching to a 4-blade prop require any other hardware adjustment in the motor / lower end? Lastly, boat does have trim tabs.

Figure mid 20's for cruise and mid to upper 30's top speed

 

[Chris1956]

I would inquire on the SR site to see if that combo was offered as the base engine on that boat. If it was the base engine, it should be adequate. 5.0L Alphas would be a better choice, IMHO.

 

[Greg Mrozinski]

I have driven both a 30' Doral with dual V-6s (4bbl) and a 30' Maximum with dual 5.0 V-8s (2bbl). They both performed equally well.