Under powered with 7.4 motors

atrick

atrick

Active Member
Mar 4, 2017
548
Penna, N Carolina
Boat Info
1998 400 Searay Sedan Bridge
1995 Searay 290 Sundancer
1990 21 maxum
2001 24' FlotBot Pontoon Boat
Engines
Twin 3116 Cats
Twin 4.3 mercrusers
305 chevy with a alpha one drive
Yamaha 90 HP Outboard
I have a question for owners of 37 to 40 foot sedan bridge boats. I am looking at getting one of the above and notice most of the ones available have twin 7.4 motors and was wondering if the boats were under powered verses 8.1 or diesels.Just would like peoples opinions on this, will be doing a lot of cruising on rivers, ICW, coast and sounds of NC. Thank in advance for you imput.
 
Depends on a lot of factors. But mostly, do you plan on long range cruising and do you plan on holding on to the boat for a good period of time. Also, how concerned are you about fuel economy?

I owned a 380 Sundancer with 8.1's and it was powered "OK", but drank gas at a high rate. That was about the largest size boat I would go with gas engines.

Now, my 480 Sedan Bridge is diesel and could never be powered by gas due to it's overall displacement (weight).

This is a common question which you can probably find some better answers than mine if you do a search on here.

Best of luck with the boat search.

Vince
 
I have a 2000, 380 DA with the 7.4 horizon motors. Power is not an issue at all, had 13 construction workers on it last summer, no issues getting on plane and up to speed. Each guy avg 225lbs..
 
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I don't think there's an appreciable difference between 7.4's and 8.1's?? At that point if you're gas, you're gas.

I slip not far from a 42 or 44 Viking aft cabin from the 80's that's gas powered. Gets him where he wants to go. Albeit slowly. My next door boat neighbor has a 410 Carver Sedan Bridge that's gas powered. I've seen him toss 12 teenagers on that thing and cruise.

Buy whatever you want knowing you're always going to be shopping for that next boat regardless of what you end up with :)
 
I owned a 95 330DA (carbureted) and a 2001 Regal 3780 (MPI), both with twin 7.4s, both with V-Drives. I now own a 2001 380DA with diesels. I can feel the difference. The 330DA and 3780 were always bow high unless I pushed the 7.4s past 3500 RPMs. I run the diesels at 2400, no issues, smooth as butter.

I was a river boater with the 330DA so the 7.4s were not a deal breaker. A dock mate had a similar size Cruisers Yachts with twin 5.7s, though his had outdrives. He ran faster, flatter and had better fuel economy than the 330.

New to me dock mate has a mid 30's length sedan with twin 6.2s. He keeps telling me how great they run at 4500RPMs, uh huh.

I cannot compare to the 8.1s, though I hear they perform better than the 7.4s. In my search for the next boat it was going to be the 8.1's or diesels only though.

Lots of things to consider, mostly how do you plan to use the boat.
 
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scoflaw said:
The 454 mag is a much better motor than the 7.4 L29. 50 more hp and forged internals
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I know that but you have to pick thru whats available in the market, personnally I'd like a pair of diesels.
 
atrick said:
I know that but you have to pick thru whats available in the market, personnally I'd like a pair of diesels.
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If you can find them in your budget than get them, you will not regret it. Again though if you are a river boater, small trips, use the boat 20+- hours a season it may not be worth your investment.
 
Gas will push them fine, but they will burn a lot of fuel. Diesel will do it more efficiently and certainly not be working as hard, but you'll have all kinds of fun working on them in the engine room of a 40 bridge, and grab your ankles when major work is needed. If you are just cruising around and trawler speed, or not traveling far each time you go out, you won't really gain anything with diesels.
 
mrsrobinson said:
If you can find them in your budget than get them, you will not regret it. Again though if you are a river boater, small trips, use the boat 20+- hours a season it may not be worth your investment.
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I'll be putting more than 20 hours a season on it, It will be docked at my house off the neuse river in NC. I put 40 hours on my 290DA in Pa a season so I like to use my boats.
 
atrick said:
I'll be putting more than 20 hours a season on it, It will be docked at my house off the neuse river in NC. I put 40 hours on my 290DA in Pa a season so I like to use my boats.
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20 hours is nothing so I would consider gas. We are putting on 170+ a year so diesel makes sense for us.
 
I do about 50-60 hours a year on my 380da. Used to avg 75 a year on small runabouts
 
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