How long can I expect a Yam 4st 115 to last?

[Docja]

I appreciate all the help I'm getting lately. I'm buying my first new boat and tring hard to buy right. I want to keep this boat and motor 10-15 years without tons of costly repairs. I'm getting a lot of advice that 2st carbs are dirty and noisey but proven and least likely to have failures 5-10 years out. However, I sure like what I hear about 4 st. My choice would be 115yam4st vs 130 yam2st and it's probably a 2-3k difference in price. I know I'd lose 2-4mph with the 4st,but the specs say the boat will run 41mph with the 4st and I think thats enough for me.

 

[DJ]

Re: How long can I expect a Yam 4st 115 to last?

Docja,<br /><br />What is the boat you are buying rated for-hp?<br /><br />If it's 150, the 115 might be a little light in power. Nothing will last that is being overworked all of the time.<br /><br />I like to power boats to at least 80% of max. Just because you have it, doesn't mean you have to use it. Resale will be better too.<br /><br />I was at a fishing camp last summer that ran Yamaha 80 hp. four strokes exclusively. Many had over 1300 hours. However, the boats were rated for 90.<br /><br />I have also run several 2-strokes that had well over 1000.

 

[JB]

Re: How long can I expect a Yam 4st 115 to last?

Ahoy, DocJA.<br /><br />With religious maintenence, and if nothing breaks you should get 3,000 to 5,000 hours before the engine is "worn out.<br /><br />As an opinion, I don't agree that a 4S engine worked hard wears out quicker than one that is "loafed".<br /><br />I agree with DJohns about powering to or over a % of max rated HP, except that I set my numbers at 70%, rather than 80%. <br /><br />I have run 16/17 Boston Whalers with 70HP 2 strokes and 4 strokes with great success and only trivial losses in top speed. Those Whalers are rated for 100HP. I know many Whaler owners who power them with 50HP and are happy with the performance.<br /><br />Good luck.

 

[Capt Ken]

Re: How long can I expect a Yam 4st 115 to last?

Two stokes or Four strokes, makes no difference on how long they last. Its the care taken and maintenance. The two stoke has been around for centuries but the newer four strokes haven't. We know what maintenance is expected on the two strokes as they get older but the jury is still out on how expensive the four strokes will be as they get some age on them.

 

[Docja]

Re: How long can I expect a Yam 4st 115 to last?

this is helpfull. Do you mean rated max or "reccomended''? I think 150 is max and115 is recc. i will check

 

[Forktail]

Re: How long can I expect a Yam 4st 115 to last?

I own both the Yamaha F115 and the 115 HP 2-stroke (virtually the same exact outboard as their 130 HP).<br /><br />The 2-stroke is a great outboard. But no comparison against the F115 fuel injected. The F115 starts better especially in cold weather, drinks about 50% less fuel, much quieter, trolls better (hours and hours on end), and has less vibration.<br /><br />I have had no repairs to either. But I do find cleaning carbs, constantly adding injection oil, frequently changing spark plugs, and the occassional hard starting and warm-up of the 2-stroke to be a pain, especially when launching in the surf.<br /><br />One of my boats is a 23' custom aluminum deep-V. I have a single F115 on it. She goes 35 mph at 5500 rpm with a 15 pitch, and cruises at 30 mph.<br /><br />I called factory Yamaha a couple years ago when I was buying my F115's and asked them about engine life in comparison to the 2-stroke 115. They said the 4-stroke F115 would last much longer due to the pressurized lubrication system and its engine design. I've never looked back.<br /><br />The F115 might cost a little more, but you get more. Fuel injection, better warranty, and a more enjoyable outboard to own. Repairs are a thing of the past. The F115 is a real sweetheart.