4-stroke outboards

[aostling]

I spotted these at the Hyde Street Pier of the San Francisco Maritime National Historic Park. At least two of these are four-strokes. As someone who grew up with 2-stroke outboards, I'm wondering what drove the change to valved engines. Fuel economy? Was Honda the first?

[dp]

Blue clouds of smoke hanging over remote lakes every fishing season, and oil pollution in those same lakes.

[kendall]

that and a four stroke gets better economy than a two stroke under the same operating conditions.

I know a couple of the lakes I used to frequent would leave an oil ring in the marinas from all the two strokes

I personally prefer a four stroke untill it's time to carry one around.

haven't handled any of the realy new 4strokes, but the one's I've handled HP for HP have been at least half again heavier.

Good thing is that the price of a two stroke has dropped into the basement, so if you're in the market it's a great deal.

Ken.

[darryl]

Those hondas are very smooth and quiet running. Probably the nicest outboard I've had the pleasure to use.

[dp]

This seems like one of the perfect applications for a rotary engine but they don't exist in this market so far as I know. A very small dual rotor engine would be light weight and compact for the rated HP but must be expensive to build, I suppose, or the lakes would be full of them.

[madman]

Yamaha 4 Stroke

I own a 25 horse 4 stroke Yamaha and a small 2 horse Honda 4 stroke. The Yamaha is very nice always starts and gets great mileage also.My Two strokes i sold years ago i had a bunch of them. Nice but heavy to lift the 4 strokes though.

[Milacron of PM]

Those hondas are very smooth and quiet running. Probably the nicest outboard I've had the pleasure to use.

Smooth and quiet at idle speeds yes, but at cruising speeds no smoother than 2 stroke and decible levels exactly the same. The 4 stroke has a more "pleasant" sound and therefore "seems" quieter, but actual decible level instruments tell a different story. 4 stroke does get better fuel economy but how much much was greatly exaggerated in the 1990's. Reality is perhaps 20 percent improvement.

Re "Honda the first"...not even remotely.....there were 4 stroke outboards even in the 1960's made in USA.

[Tim Clarke]

A guy I knew had a old 4 stroke, about a 10 hp in size. Looked like it was made in the 50's or early 60's. I don't remember the brand. Air cooled, if I remember correctly.

As was mentioned above, 4 strokes are heavier. The 15 Merc I had on my little boat weighed about 75 lbs. The 8 hp Honda I use on my bigger boat for a kicker is alot heavier, maybe as much as 15-20 lbs. As for noise, different brands of outboards have different noise levels. Much of which is due to some having better noise control treatment, like foam padding under the hood. The 15 hp Merc. was a new design when it came out in the late 80's [I think] It was quiet, smooth, started with a couple yanks, and was more fuel efficient than the 9.8 that it replaced. Using the semi-synthetic oil reduced the smoke and stink factor alot.

Given the cost and weight factor, I wouldn't hesitate to buy another if they were still available. Kinda like the ole '66 Ford p.u. I had years ago. Great rig in it's time, and still fine if you have one in good shape, but technology has passed old trucks and 2 stroke outboards by......

TC

[Carld]

"I spotted these at the Hyde Street Pier of the San Francisco Maritime National Historic Park. At least two of these are four-strokes. As someone who grew up with 2-stroke outboards, I'm wondering what drove the change to valved engines. Fuel economy? Was Honda the first?"

As I understand it was the EPA and tree huggers that pushed 4 stroke engines. There is a move underway to outlaw all 2 stroke use and manufacture.

[Al Messer]

Would this proposed ban also include model engines?

[Milacron of PM]

A guy I knew had a old 4 stroke, about a 10 hp in size. Looked like it was made in the 50's or early 60's. I don't remember the brand. Air cooled, if I remember correctly.

TC

Maybe a Bearcat, but they were larger than 10 hp and water cooled.

www.4cyclemarine.com/bearcat.html

There were small air cooled 4 strokes back as far as the 1920's but mostly by obscure companies.

[Carld]

Dave Brown in one of his columns said there is the posibility that after the EPA gets all the 2 cycle engines off the road, yards and water they may come after our 2 cycle model engines. I doubt if they really would because there are so few model engines compaired to the other uses. Knowing how driven the tree huggers are if the EPA came after our model engines then the huggers would take it on themselves to visit all model airplane fields and report any violations. However, I won't be holding my breath waiting for it to happen, if it ever does.

The ones it will really hit are the large models that use the big gas 2 cycle engines. I use a few of them myself.

[reality checker]

Mis-information about two strokes

http://www.evinrude.com/en-US/

The new 2 strokes beat 4 strokes in fuel economy, emmisions, weigh less, and have much less maintenance required and they accelerate faster.

Some of assumptions posted were true at one time, like a 1969 427 c.i. rat motor compared to a new fuel injected computer controlled engine.

I think you would be making a big mistake to not consider a modern 2 stroke when shopping for a motor. Especially if you consider the facts, not just what you remember from your youth.

[J Tiers]

2 stroke are fine...... no more emissions than any other engine........

.........IF..................

IF they do not mix gas and oil, but are separately oiled. (Oil does not burn well, and pollutes badly, as well as reducing the efficiency of burning the GAS.)

IF they do not suck in gas-air mixture to the cylinder. (because that inevitably "carries-over" raw mixture to the exhaust).
.
.
.

In other words, 2 stroke DIESELS are much better candidates for clean than a 2 stroke carbureted gasoline engine.

[Old Doug]

Twim F90 Yamahas

The owner of our 86 22 Grady White replaced the 2-st 115s after over 3000 hours with F100 (now F90) Yamahas about 6-7 years ago. Sadly, Bob passed away suddenly two years ago. I fished off-shore with him several times. The fuel ecconomy was at least 1/3 better than the 2-st 115s. The boat would still top out at 45 knots on flat water. You could hold a normal conversation at cruise going off-shore at 30 knots.

Bob put over 1500 hours on these engines in 4 years. He won the Big Bend tournament out of Carrabell, FL two or three times. Probably caught 6-8 Marlin off (40-70 Miles) from Mexico Beach, FL. Great boat, Great motors, and a truly great guy.

Son owns a F25 Yamaha and loves it.

New poster, and newbie lathe/mill owner. Old Doug--Griffin GA