Join Date: May 2002
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Re: Electric start or easy start outboard for 21 foot sailboat
I think you are correct in that it will be difficult to impossible to find an outboard with electric start smaller than an 8hp. I have an electric start 8hp for my 23 foot sailboat, and it is plenty powerful; it pushes the boat at hull speed at about 3/4 of full throttle.
For your boat, you could do with a 6 or maybe even a 4 hp engine, depending on the prevailing conditions. If there is a strong local current, or if the tides are strong, you should go with the bigger engine. You don't want to buy too big an engine; but according to sailboatdata.com, your boat weighs 1900 lbs. It can certainly handle an 8 or 9 hp engine on the back. And for what it's worth, I love it the electric start feature on my engine. But there are a few things to consider that you didn't mention:
First, you have a two stroke engine now. If you buy a factory new engine, it will be a four stroke. No one makes small two stroke engines anymore. They phased them out about ten years ago. Four stroke engines have some advantages over two stroke engines: they are quieter. Much quieter. They pollute less. You don't have to mix oil into the gas. And for a given HP, they generate more torque so you can get more oomph at a lower cost. All good stuff. But the flip side is they are heavier than their two stroke counterparts. So, given the extra weight (how much extra depends completely on the brand and size) and torque, you may need to upgrade your transom outboard mount too. This can be simple or difficult, again depending on the mount you already have.
One more thing to consider: always get the long shaft model. The "standard" shaft length on an outboard is 15". The long shaft models are usually 20". Some come with an "extra long shaft" option of 25". The proper model for you depends on your mounting set up. Do you have a moveable outboard mount that lets you raise the outboard out of the water, or is it fixed? If you raise the outboard mount or tilt the outboard up, will a 20" shaft be clear of the water? Will a 25" shaft? Take some measurements before you go shopping. Generally speaking, the deeper the prop, the more efficient it will be, and the less likely it is the prop will come out of the water in rough conditions or when making sharp turns.
One other issue you raised: will a higher hp engine run "slow" enough for you to get in and out of your marina? The short answer is yes. Even those monsterous 300hp outboards can run slowly.