2 stroke or 4 stroke ?

[Randy]

I like those Shamrocks Scoffshore , I had an opportunity to grab one for cheap a few years ago because the guy just bought a bigger boat and just wanted it gone. I passed on it and regret it ever since. Very simple drive stable and a dream to troll . (stays straight ) My buds was an excellent offshore boat has a 302 inboard . It was a little wet though. The low center of gravity and the keel made it stable and the beast was ALREADY practically on plane. The entire transom was clear with no outdrive or engine to fish around. I also dont remember ever having to worry about fuel. It was miserly. I can imagine a diesel in that boat makes it a "go whenever you feel like it" boat. I love the speed of the outboards but i dont see anyone posting 4000 hours on one yet without a rebuild. I asked anyone with an outboard with 4000 on it to post and got nothing so i'll drop it to 2000 hours. Anyone with just 2000 hours on an outboard without a bebuild ? Randy

[wahoo51]

Randy,

You seem to be the exception and darn close to my previous statement bellow.

"If we all used our boats every day, maintained them perfectly, never let our bottoms foul up, and always kept them at a low cruise speed we may see FWC inboards lasting 4-5-6000hrs."

But most people use their boats when the weather is good and most people are not very good at maintaining their boats.
If you go to any boat ramp on a good Sunday afternoon you will realize that most boaters don't know what the hell they are doing. Could you imagine how they maintian their boat engines.

BTW, my statement on longevity of diesels was directed not only to the weekend warriors w/diesel engine boats but to the marine diesel engines w/higher cruise speed; this being the case for most modern diesel engines.
Please exclude tug boats, commercial (slow) fishing boats, and anything that has tires. I was refering to the marine majority.
If any one has diesels that cruise below 1200rpm, use them more than once a week, and follows the maintainence schedule to the "t", please disreguard my diesel longevity statement.

"I asked anyone with an outboard with 4000 on it to post and got nothing so i'll drop it to 2000 hours. Anyone with just 2000 hours on an outboard without a bebuild "

You may get a hit or two. But i've really (personally) never seen one w/more than 1500hrs. After 800hrs i trust them as far as i can throw them. I just can't imagine something that cruises at 4500rpm lasting very long.
BTW, just to make it interesting why don't you exclude the "my buddy has a friend that has a ....." crowd from this survey.

One last thing to cover. Shamrocks. 22 & 26 hull. I love them and hate them. I love their stability, fishability, economy, and basic layout.
I hate their speed, flat bottom, and most of all the cramped engine bay. Maintainence is a real bitch on the 26.

Can i get an Amen?

[CaptKen]

Randy
Drop by boat center on 441 near 595 and ask the tall skinny guy behind the counter about the police boats with the yam 225 4 strokes that his mechanics worked on in school. I think if you do you will be amazed.

[Randy]

Hi Kenny, I heard you out there a week or two ago and tried to radio you to tell you we were on the 53 and gettin HAMMERED but didnt get u. The Boat Center is right here by my house and the guy your talkin about i buy from all the time. When my buds TWO 250s shrapneled at 500 hours he's the one i asked first about the 250s . He said they were "bulletproof" . He's a Yamaha dealer and didnt wanna talk about it. So.. I went home and did a Google search " Yamaha 250 failures" and came up with thousands of complaints on the 250-225 with the consensus the 200 were good but the 225-250 had a problem with one cylinder overheating. When i was in Marine mechanics class we were rebuilding a guys 225 that had had a lower crankshaft seal go bad at 600 hours allowing water to ruin the crankshaft . He was trying to buy one and finally ended up buying a USED one for 900.00 ! Im not targeting Yamaha but inquiring into ANYONE with just a measly 2000 hours on a hour meter without a rebuild to respond. Theres a lot of people here and im just lookin for ONE. Im doing the math and for just 2000 hours on a motor that cost 11000.00 thats aprox 2 days a week for two years or 1 day a week for four years. Thats if anyone can tell me outboards get 2000 hours. So far Zip ! Thats 52.88 PER week the motor costs if it lasts 2000 hours for two years and half that much if it lasts 4. Thats 2.64$ per hour before gas , oil , maintenance. So far the overall consensus is only possibly 1500 hours! Theres a lot of people runnin all brands of outboards here on this forum does ANYONE have a outboard with just 2000 measly hours on the meter i can see ? 11000.00 is a big chunk o change for something that wont last 2 years if you use it two days a week. Again i ask does anyone , anyone out there have a outboard with just 2000 hours on the meter i can see ? There's literally THOUSANDS of outboards on this forum . Some boats with singles, twins or even triples . Randy

[CaptKen]

Randy
Im with you, In 30+ years of boating, all three major brands and never more than 2000 hours and been down the rebuild road to get another 1000 hours maybe, Thats why I went the 4 stroke route. Ive heard stories of 4000+ and one of 5000+ I hope its true cause im not your average weekend warrior where 2000 hours would get a guy 10 years, The road im on now with 1000 hours if it were a 2 stroke it would be shot before its 1/2 paid for.
I know you either Love um or hate um, Im one that Loves um, The way I feel right now, I would never buy another 2 stroke unless maybe it was 1/2 price to get close to your cost ratio of $ vs hours. If mine blows @ 2000 hours it would still be a better deal on oil alone, 6 quarts every 100 hours vs 16 GALLONS or more every 100 hours.
Mine is pushing 1000 hours and never had to go back to the dealer once, not too many engines could claim that by itself.
You should factor in the cost of spark plugs and oxygen sensors for your 2000 hour analyss on a 2 stroke, I know someone that did once and came up with like 5 grand for plugs in a 2100 hour life of a pair of 2 strokes not including oxygen sensors.
I put 1 set @ 500 hours and they were still like new

[Randy]

Im leanin toward a straight inboard Ken , Everyone is different and uses their boat for different things . I no longer strive for shallow water and now all my boatin is offshore so "bangin on the bottom" isnt a issue. I gotta have some serious runnin time , speed isnt important , 20 is fine if it sips gas like a drink mixin straw. Im watchin those 4 strokes with hope . They are new technology and that for that price spooks me but maybe they will be the answer. I think soon with fuel prices goin like a Apollo moonshot everyone will be havin to take into consideration fuel before plannin a trip. I dont wanna have to consider fuel costs whether i can go out or not. All i wanna watch is the weather window and go. Right now i can. Dont forget it's my turn to take you along on ol Teaser . Let me know when you wanna go and if this Hurricane/tornado/Tsunami weather EVER SETTLES we're off !! Randy

[RiskTaker]

Randy:

It sounds to me that you would be really happy with a Power Cat. that had twin inboard Yanmar Diesels. I have seen them on sailing Cats. before but not sure if the option exists as a production power Cat at this time. But if you need to retrofit a standard Power Cat., perhaps you could start with these:



I'd be willing to guess get that you may get 2000 hours plus on these.

Not quite sure if you would get to 20 kts. , but you would certainly be sippin' fuel. ( and you could spend more time sipping Mojitos.)

And if that gets too expensive, we can always start swordfishing on my blowboat: its got a single 25 hp inboard diesel, but can only do 6.5 knots. So you have to expect it to be more than a 3 hour tour, more like a 30 hour tour. But we will probably only sip about 6 gallons of fuel, without having to host any sails. irat: But 15-20 kts. would be best.
http://www.yanmar.com.au/marine/lhas...hastseries.htm
http://www.yanmar.com.au/marine/lha_.../lhaseries.htm

[Randy]

Thats interesting RT. I didnt know they even made such a thing. I think a straight inboard diesel 20 kt cruise , clear transom (no motors or drives) stickin out the transom to fish around ,maintenance =change the oil and filters for 10 years is what im thinkin of. Those puppies run 18-2200 RPM for thousands of hours. I dont know what those diesel outboards turn but do know the lower unit 90 degree gearing on outboards removes 10-15% of the HP and are pumping saltwater through the powerhead. The thing i like about the inboards are they lose no HP going through a lower unit , they sit real low in the boat making the center of gravity low so the boat doesnt like to rock, they are freshwater cooled (antifreeze) so they dont corrode and burn comparatively inexpensive fuel at tiny sips. Those diesel outboards look top heavy , are pumpin saltwater through the heads and have 10-15% power loss through the lower unit . I think the single inboard unit may be better. Granted deisels have shortcomings too , They are loud , heavy, anyone whos ever captained a single inboard with a RUDDER behind the prop knows it's a whole new trick backing up , You HAVE to keep the fuel for a diesel FREE OF WATER , etc. . But for what im doing BUKU hours/days offshore it may be the way for me to go. Just For anyone who wishes to know , Diesels are also 2 or 4 stroke . (2 strokes, "Detroit" tend to be messy with oil leaks) They are reliable to the point ive known one guy burned a hole through a piston and continued to use the boat 6 months doing comercial work. It smoked and used oil but continued to run finishing the job. A rebuild on a diesel when it finally goes after thousands of hours is usually averages 2000.00 per cylinder ! Clearances on a diesel are tighter then a gas motor . Comercial applications of diesels (nonplaning hulls) usually use no raw water pump at all but rather simply use the engine circulating pump to pump antifreeze through a pipe welded outside the hull for heat transfer. There is no Saltwater ever entering the engine or tranny cooler and exhaust is expelled through mufflers . Planing hulls of course use a raw water pump through the cooler cooling the antifreeze that cools the engine and tranny cooler finally dumpin the raw water into the exhaust manifold to be expelled with the hot gasses. No salt water ever enters the engine at all BUT does enter the exhaust manifold. Please forgive me if you know this i just thought anyone not familiar may find it interesting. Diesels turn slowly and last a long time (many , many thousands of hours) so antifreeze to stop corrosion is imperative while gas inboard motors turning WOT 3800+ RPMs are usually wore out before the time corrosion destroys the motor so it's irrelevant to use fresh water cooling on gas . (of course unless you just idle around the intercoastal at low RPMs for years) Again this is just for those not familiar with diesel setups. It's just some interesting scoop some may find interesting. I thought since we're all sittin here lookin at our dry boats and dreamin of MONSTER SWORD FISH TRYIN TO SHOVE A 4FT SWORD THROUGH OUR TRANSOM some may find it interesting so please if not just disregard it . I dont mean to bore anyone. Outboards also amaze me as a 250hp 2 stroke powerhead i can put under my arm and walk around the block , I dare anyone to try that with my Ford 230 hp inboard ! Hahaha!! That much HP from something that light is absolutely amazing . Randy

[RiskTaker]

Randy, I'm with you on the the straight inboard turbo diesel solution. I suspect that may be the most economical solution between I/O and outboard options.

You seem to have a lot of facts at your disposal, and for translational energy losses. Would you happen to be aware of translational losses of a straight shaft configuration? (Any transmission losses) I have never worked on a Marine transmission before so I do not know what the inner workings are for Foreward/Neutral/Reverse. Ideally, the loss would be designed to be negligible for Foreward; however, I do not know. Please enlighten us if you know.

[Randy]

Hey RT , ya got me i dont know the particulars on the different inboard transmissions but do know loss of straight shaft power is small compared to the 90degree on a outboard and the TWO 90s on my IO. Maybe some of the guys already running inboards know the particulars. I only know what i've been involved with (comercial applications) and a few buds with diesels and limited to what i've actually worked on. I do know some of the guys are having big praise for the new John Deere diesels but again they are high RPM and i gotta see after a reasonable time how they hold up. A bud has been runnin them for 4 years now on his tug with NO problems but 4 years is not long enough for me to decide if i trust them. THEY COST SERIOUS $ and they have to last a long time to make them financially feasable. One more interesting thing about diesels is gonna be hard to believe but diesels wear out faster when theyre not running . Diesels on start up wear and corrosion on crankshaft and bearings from sitting take more from the motor then if it continually ran. You have to run them . Some manufacturers and aftermarket dealers now have pre oilers to get oil pressure before it starts so the initial start isnt so rough on the engine but just sitting without running actually does more damage then running continually. Also ,Lower units on outboards have a 90 degree angle gear that takes HP from the engine, The HP loss increases as the gears wear and the shimming becomes sloppy . Most people using 2 strokes start to think their motor "feels" less peppy . 2 strokes are exactly that the faster they take air in and get it out the faster it is. Over time the exhaust housing builds up a layer of residue in your exhaust housing and like any 2 stroke expansion chamber restricts exhaust gas and your 225 hp becomes a 220 -215. Also 2 stroke oil has a wonderful habit of building a "crust" under the rings over the years (especially if you use cheap oil) and one day the crust wont let the ring compress and "snap" the ring breaks and destroys the cylinder walls. This is why it's imperative 2 stroke owners run engine tune through the engine once a year to remove the build up under the rings and remove the build up in the exhaust housing( expansion chamber) to keep that 225 a 225. That of course isn't gonna fix the wear in the lower unit which as the shimming get sloppier and sloppier will rob power from the prop just like a worn rear end on your truck. That requires a outdrive mechanic . Trust me lower unit shimming is no task for amateurs . It requires special tools and experience. I tried a class and finally stopped when i hit a Preloaded alpha drive. It's hard. Todays units are shimmed under load , that means the correct clearances are set while the shafts are under load. Todays lower units unlike the old times are at correct clearances while running and not to correct tolerances while idling. It's better technology as the unit is at proper tollerances while under stress unlike the old days when you were running the clearances were off. The units last longer. I can pull a lower unit down and go through it but when it's time to put it back together the final shimming i leave to Mike over at Ravenswood Sterndrive. He knows lower units big time and he's never let me down over all these years. Thats a lot to say about a marine mechanic today. Im no marine mechanic but i know a little and i can say he has never told me anything that wasnt true. If you need lower unit work seek him out. Lower units need to come down once a year, not just for the water pump but also leaving them for longer may necessitate heat and a chisel to split the housings. Not fun to watch on your shiny outdrive, especially when you know he's hammerin on a japanese aluminum housing. Every year a new pump and clean and grease the housing bolts/holes before putting them back together. Got me goin on here man . Hope some of this info helps someone. My typin fingers tired ! Randy

[Beer Bones]

I will say that i am very happy with my 150 E-Tec. Just put it on a 19' spanish wells skiff and the boat skip's along. Great trolling and nice and quiet for deep dropping. I have been using it constantly and can't seem to empty the fuel tank. I hope everything stays the way it is but if it does crap out you guys will know right after the dealer.

[Whitewater]

All transmission systems have some power loss, just the viscosity of
the oil on gears would create some loss. However, if I remember
correctly wasn't the power ratings on outboards changed not long
ago to be prop power? Most I/O's and inboards are rated at the output
shaft.

As for longevity, my last boat had a 200 Hp 1983 Johnson. It was used
almost every weekend from May till Oct (our boating season in MA)
it was 17 years old when I sold it. As for repairs, Replace starter,
trim unit, and had the seals replaced on the lower unit. Power head
still had great compression. It just appears that there are some good
ones and some trouble one just like cars.