Iam looking for a new motor any suggestion?

[DougK]

Hi I am looking for a new motor for my 1977 Sea Ray SRv 24ft The boat has a OMC 235 outdrive and a 351 winsor Ford Also it has hydrolic trim tabs but I can't seam to get the milage out of her or the speed I would like. Top speed is 26 at 4100 rpm's and with 115 gallons of fuel were running about 15 gallons an hour on her now. up here in Alaska thats not a lot of time or distance. Any Ideas on how to improve this?

 

[walleyehed]

Re: Iam looking for a new motor any suggestion?

What's the max RPM range on that engine???

 

[Bondo]

Re: Iam looking for a new motor any suggestion?

You're starting with a less than desirable engine,<br />turning proabably the worst outdrive ever built......<br />You're options are severely limited.......<br />Sorry.....

 

[1Moredrift]

Re: Iam looking for a new motor any suggestion?

I have a mercruiser Horizon 350 MPI (300 hp at prop)with a Bravo 1 drive on a 24 ft Grady White. At 3400 RPMs I am burning about 12 GPH and moving at 26 MPH. My top end is 40 mph at 4800 rpm. Boat weighs about 5500 with 150 gallons of fuel.<br /><br />As hinted at earlier, check your motors specs for maximum rpms, if you not in that range at wot then you are probably running slower and less efficient than what you should be.<br /><br />You can probably fit other packages into your boat (Volvo Penta or Mercruiser)but you will need new motor mounts and possibly transom work which would be alot to put into an older boat.

 

[DougK]

Re: Iam looking for a new motor any suggestion?

Well thanks for the responces I can do the engine and the hull work but I need to find out what you guys would think is the best. I can built a small Block chevy or rebuild the ford all so I have actcess to a older valvo penta out drive Iam not sure which one it is I just want to enjoy my boat again. I'am not sure but I think the max RPM's for the motor is 4800.

 

[JasonB]

Re: Iam looking for a new motor any suggestion?

The 351 isn't a bad engine, but I wonder if you have too much boat for the motor. If it in need of an overhaul for some reason, you can get more from it with the proper components. Can't speak to the drive. I push a 19' to almost 50mph with a 302 and get 2-4mpg at a 32mph cruise, never figured GPH. Not bad for a boat that runs over 3000lbs wet w/36 gals of fuel and 500lbs of people plus a couple hundred lbs of gear. <br /><br />Your RPM leaves a little room for improvement as I think Mercruiser speced the 351 Windsor at 4200rpm or maybe 4400 when they used them, can't remember off the top of my head. Make sure you aren't lugging her.<br /><br />Also betting you have a 2bbl carb. Maybe an upgrade to a 4bbl to get some more uumph? May hurt fuel economy though. Also, just a basic suggestion you have likely looked at, have you done a complete tune up lately?<br /><br />I would work with what you have instead of going through the headache of converting to Chevy power and/or another drive. If it works, use it until it doesn't While parts aren't as plentiful for Ford engines, They are readily available and I have no complaints with my Ford Marine motor, but mine was rebuilt to my specs.

 

[JasonB]

Re: Iam looking for a new motor any suggestion?

If you are 700RPM below the spec, soundls like a re-prop may be in order. Getting her up in her recommended RPM range may help the fuel bill while bumping speed up a bit.

 

[kenimpzoom]

Re: Iam looking for a new motor any suggestion?

You should be able to hop up that 351W pretty easily, it is a popular engine in hot rodding.<br /><br />Get a 4 bbl carb, hi energy ignition, perhaps a cam change, polish up the heads, increase the CR to as high as a marine mech suggest, and high flow through hull exhaust.<br /><br />This should get you 25-50 more HP than a stock 2 bbl carb.<br /><br />But as the others say, you may be overpropped already.<br /><br />Also, is there some other reason for the slow speed (bottom growth, overloaded, water trapped in foam, etc....)<br /><br />Has it always been this slow?<br /><br />Ken

 

[DougK]

Re: Iam looking for a new motor any suggestion?

Well thanks for the input I was told from my mechanic that the carb I have is an auto not marine carb and that the bout cam out with a 14/13ss prop from the factory. Iam afraid of putting to much horse power in to that old 245 omc out drive but with the computer spects I have seen I can easliy put 320 horses out of the engine I will read as much as I can about pro changes and get back to you later. Again thanks guy for your help all so I don't have any growth on here shes allways trailered and I even removed the bottom paint so it has to be the prop or a weak engine we'll see come spring . thanks Doug-k