Date: Tue, 5 May 2009 14:27:12 -0600
Greg,
Don't just take my word or opinion, but you can look up SAE papers on VSR (valve seat recession) around the world and the effect of taking the lead out of fuels.
There's also a trait that engines exhibit known as "lead" memory. Although most of our US boats haven't used leaded fuels for years, some automotive engineers have shown that engines that once ran leaded fuels, don't suffer from lack of valve lubrication on unleaded fuels for tens of thousands of miles, if ever.
Octane ratings are also an interesting subject. Our engines were built with typically under 9.0:1 compression ratio. (I think the 307 Chevy was 8.5:1) If an engine gets really carboned/coked up it CAN increase the effective CR and lead to pre-ignition, which higher octane fuel can help prevent. But, again I am assuming properly tuned engines, running correct ignition timing and correct Air/Fuel ratios under normal loads and properly working cooling systems.
I don't mind paying a few dollars a boating season more to throw in premium but I also don't mind or worry about running on regular octane. But throwing in octane booster fuel additive is unnecessary IMHO, unless you are running a supercharger or have installed higher compression psiston/cyclinder head combinations.
Also, at my altitude here in Salt Lake City our refineries are typically producing slightly (1-2 pts) lower octane fuel, compared to sea level or lower altitude environments. The air denisty drops roughly 4 % per 1000 ft above sea level, which effectively lowers my need for higher octane to combat pre-ignition. It also effectively turns a 5.0L Chevy V8 into a 3.7L Buick V6!
----- Original Message -----
From: Gregory B. Fell
To: Lee Shuster
Cc: 'Evinrude & Johnson Boats of the 1960's and 70's'
Sent: Tuesday, May 05, 2009 1:07 PM
Subject: Re: [OMC-Boats] 1970 Evinrude Sportsman 155
I don't have your knowledge and am in no position to dispute. I have just always thought that the engines built before the conversion to unleaded (early 70's???) required the lead. I'm probably too scared to stop adding the lead substitute. I have been wondering about the octane, though. I think I recall the manual calling for a very high octane rating --- it's been a very long time since I've looked --- but something like 98 octane maybe???? This is a good topic. I think I'll look at the manual again. I've been meaning to scan the darn thing at the office for over a year now, as it's coming unbound. I think this will give me the excuse to do it.
Gregory B. Fell
The Fell Law Firm
3300 Oak Lawn Avenue, Suite 700
Dallas, Texas 75219
PHN: 972-488-8177
FAX: 214-219-4218
GFELL@...
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Lee Shuster wrote:
This is an interesting topic. I can't resist (politely) offering a differing point of view, Greg.
Personally I have never seen or heard of a case of a OMC/MerCruiser/Volvo GM Marine engine built before 1973-75 (when hardened valve seats became standard) that suffered from valve seat recession due to running on lead-free fuel. Usually pre-ignition or pinging is not a problem, either; assuming the engine is running stock ignition timing and your cooling system is working properly.
I WOULD run middle-grade (88-89) or premium-grade (90-91) octane fuel when it is conveniently available, but I wouldn't worry about additives or the occasional tankful of REGULAR (87) grade gasoline.
Using STA-BIL or SEA-FOAM is a good idea to prevent stagnant varnish build-up over long storage periods, but the idea that you should worry about valve lubrication for non-hardened valve seats is sorta like the warnings we got about Y2K. (I have used such additives on vintage air-cooled motorcycles, with good results, but I don't find it necessary on boats.)
Also, I am concerned about the adverse health affects to yourself and the environment that some fuel additives may have.
Tell you what, just send your fuel additive money to me or better yet donate to Phil's website!
Lee Shuster
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From: omc-boats-bounces@... [mailto:omc-boats-bounces@...] On Behalf Of Gregory B. Fell
Sent: Tuesday, May 05, 2009 9:51 AM
To: Evinrude & Johnson Boats of the 1960's and 70's
Subject: Re: [OMC-Boats] 1970 Evinrude Sportsman 155
You need to use lead substitute for lubrication. I also add octane booster.
Greg, '69 Sportsman 155
Gregory B. Fell
The Fell Law Firm
3300 Oak Lawn Avenue, Suite 700
Dallas, Texas 75219
PHN: 972-488-8177
FAX: 214-219-4218
GFELL@...
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This communication does not reflect an intention by the sender or the sender's client or principal to conduct a transaction or make any agreement by electronic means. Nothing contained in this message or in any attachment shall satisfy the requirements for a writing, and nothing contained herein shall constitute a contract or electronic signature under the Electronic Signatures in Global and National Commerce Act, any version of the Uniform Electronic Transactions Act or any other statute governing electronic transactions.
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William R. Lindow, DMD wrote:
Hello to all,
I have recently purchased a 1970 Evinrude Sportsman 155 which appears to be in very good condition. I will have many questions and some of them are fairly basic but the first one is refueling the boat. It used to run on leaded and is unleaded safe for it and there appears to be two different places to refuel- one in the bow and one in the stern. The boat is running well at this time and appears that it only had one owner.
Thanks,
Bill
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