repowering my 20v CC have a 150hp 2stroke want to go much smaller

M

MoonGlow II

New member
I have a 1980 20v CC with a Suzuki 150 hp 2 stroke runs great and fast BUT the price of gas is killing me and keeping me off of the water. So I am thinking of going much smaller as in the 50 to 90 hp used 4 stroke motors....I dont care about speed as much as having enough power to make it out the inlet in a strong tide and to be safe in case the weather turns bad and the seas get rough. We use the boat for near shore SCUBA diving and intercoastel crusing. staying within 3 miles of shore. Would like to hear all you thoughts on the on my idea. Thanks and happy boating!
 
My experiance over the last 30+ years---

Do not go smaller--especially if you are hauling dive gear--and a 4 stroke smaller than what you have--good luck getting on plane or much of anywhere.

If you have a smaller engine and you have to run it at full throttle all the time to get somewhere versus a bigger engine that you pop onto plane and pull the throttle back to cruise (which might not even happen with the smaller motor) and burn the same or less fuel.

Also take into account the cost of the new motor--how much fuel will that buy??

I personally would not go smaller than a 150hp on that boat--especially if you are hauling divers and gear. It could just be the old carbed gas hog outboard---in which case--you will have to bite the bullit and buy the fuel--or a newer injected motor(which kills my earlier statement).

You have to do what YOU think is right.

Just remember that our boat motors are not like a wheeled vehicle engine where you go up hill, on the flats and down hill--they are always going"UPHILL".
 
MoonGlow II said:
I have a 1980 20v CC with a Suzuki 150 hp 2 stroke runs great and fast BUT the price of gas is killing me and keeping me off of the water. So I am thinking of going much smaller as in the 50 to 90 hp used 4 stroke motors....I dont care about speed as much as having enough power to make it out the inlet in a strong tide and to be safe in case the weather turns bad and the seas get rough. We use the boat for near shore SCUBA diving and intercoastel crusing. staying within 3 miles of shore. Would like to hear all you thoughts on the on my idea. Thanks and happy boating!
Click to expand...

Keep the motor you have...gas prices are about to decline somewhat for one thing...and try simply going slower...as you surely will w/a much smaller motor. Keep your RPMs down just enough to keep her on plane...high RPMs really burn the gas...you'll need to juice it up to get on plane, but once you do, throttle back and lighten your load as much as possible...
 
An engine that size will not let you get on plane with the V20, especially with a 4 stroke.
And especially with anything other than an empty lite load hull.
You will use more fuel as has been said but also will use more because you have a hull designed to be efficient at planing speeds, at slow off plane speeds it will be plowing the water.
A good condition 115 hp TWO STROKE!! will be the minimum, they are also very good on fuel. BUT, if you anticipate heavy loads such as people and dive tanks and gear etc. a 150 would be the minimum. IMHO
 
How fast are you trying to go with your 150? I know teh SUZUKI 150 is the biggest 150 there was at 2.7L's, but it was also said to be decent on fuel for it's size. Fuel burn on it should be around 10-12 GPH or so at a 3800-4000 RPM cruise, a 4 stroke will probably get you down to about 6-9 GPH at the same speeds. And like stated above, 90 is the absolute MINUMUM to get a V on plane. And it won't live a happy life doing it. If you don't boat alot, then you will never get your investment back in buying a new engine. Fuel isn't that big of an expense in all reality in owning a boat when you sit down and add up everything you spend money on when boating. Upgrading engine because of fuel costs rarely if ever pays for itself for a recreational boater.
 
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