4 stroke weight?

[XJoker25xx]

I know 4 strokes weight more than 2 strokes but is it really that much of a differance in wieght?

 

[PAkev]

Re: 4 stroke weight?

I'm not a motor guru but will put my .02 in:<br /><br />Although 4 strokes have a little more hardware which contributes to the weight, it does not necessarily mean they all weigh in more than a 2 stroke with the same horsepower.<br /><br />For Instance, the Yamaha 150 hp 4 stroke is 466 lbs and the 150 hp 2 stroke HPDI is about 10 lbs heavier.<br /><br />Older 4 strokes have had the reputation of more weight to HP ratio but the tide is definately changing. The issue you have adressed has been a major concern among manufacturers who are now making the weight of their 4 strokes competitive with 2 stroke alternatives. <br /><br />Happy New Year<br />Kevin

 

[JB]

Re: 4 stroke weight?

The Suzuki/Johnson DF140 weighs about 410lb. Lighter than some 140 2 strokes, but most 4 strokes weigh more than comparable 2 strokes.

 

[BRIAN03]

Re: 4 stroke weight?

I only deal with the v-6 engines. The fours weight more. They are slower horsepower to horsepower. If you are repowering from two strokes they some times hit when turned all the way. Much wider cover design. They will burn the same amount of fuel on the bigger boats. Say a 30 foot. You turn a four stroke higher for the same horsepower. The prop has a rotational efficence. Where it like to run to be the most efficient. The four stroke run the prop higher in rpms to make the same horsepower. The fourstroke takes the prop out of that sweet spot because all the props are designed for two strokes. When we repower with fourstrokes it takes for ever to find the right props. Horsepower to horsepower. We have had customer make us take his fourstokes and put two strokes back on. HPDI's. Look at the post where they played the prop game. They thought it was the hull,the height,the cables, it turned out to be the props. It is going to take a while till they get the props correct on the four strokes. They are quite at idle. I'll stick with my two strokes. When they come out with varible cam timing and lose a 100 lb's on the v-6s I will buy one. My HPDI's will suck the headlights out of any four stroke on the way by and burn the same amount of fuel above idle.

 

[rodbolt]

Re: 4 stroke weight?

hello<br /> gotta agree some with brian. the prop selection on the 4 strokes bites. it is very difficult for us techs to properly prop a 4stroke with 2 stroke props. sometimes it take 6 0r 7 tries. especially if the boat is heavy as the 4 stroke wont rev up enough to get in a power band if the boat is heavy/loaded with the wife and kids and inlaws and a couple nieghbors. 4 strokes are ok but they are not a panecea for no maint. and you will find that 4 strokes are going to be throw away motors. it will be very costly to overhaul one. we figgue about 40 hours labor on a 115 yammi if the manual is followed. the big gig is the oil sump cleanig. I have already seen one engine fail twice after a so called rebuild that never had the oil sump removed and cleaned of metal shavings. so are 4 strokes worth the weight?<br /> not in my opinion. but we may as well get used to them. they are going to be the only choice soon due to the uninformed chuckle heads that are making our laws.<br /> I argued for months about a law here for jet skis. the idea was to make them idle about a mile out the creek. the big arguement was pollution. no one would believe me when I tried to explain that the motor polluted less at wot than idle.<br /> good luck and keep posting

 

[bossee]

Re: 4 stroke weight?

rodbolt <br />I'm sure 2-strokes will be on the market for many years in the future. For example Mercury Optimax 75 - 135 hp 2-strokes is CARB 2008, 3-star, rated now. And as far as I know that is the most strict rating today. I hope Mercury have the Optimax 150, 175, 200 and 225 also 3-star rated soon. And other manufacturer of 2-strokes also. I use 4-stroke myself, a Yamaha F115 2003 that is CARB 2-star rated - but 2004 model is CARB 3-star rated now. With more and more 2-strokes that use Direct Fuel Injection and similar and more and more get CARB 3-star rated it is not that many advantages with 4-strokes left compared to a modern 2-stroke.

 

[pine island fred]

Re: 4 stroke weight?

my own experience here. the xtra weight of a 4 stroke certantly make a difference on a smaller ( 16 ft. ) boat. nothing wrong with the motor but i am back to a 2 stroke, and will wait until the 4 stroke weight is reduced.

 

[BRIAN03]

Re: 4 stroke weight?

Long live the TwoStroke. You dont need to adjust the valves or break in the cam.