two stroke motors

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sinkingfast

Seaman Apprentice
Joined
Dec 31, 2003
Messages
34
Hello Guys,<br /><br />We are two stoke racing engineers and our forte has been racing motorcycle engines. We have powerboats too and sometimes our work is on marine.<br /><br />Since reading a lot of the comments regarding setting up a two stroke engine on the mixture/oil burn side, we think I have a lot of experience that some of you guys might find useful.<br /><br />We have always got maximum horsepower out of two strokes without compromising the reliability…. and sometimes the answers for the mechanics and causes for seized motors that has had you scratching your heads.<br /><br />If any of you want information to help set up the motor, give me a shout on<br /> info@robertsracing.com<br /> and I will do my best to answer them free of charge.
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: two stroke motors

Hello, Geraint.<br /><br />It is very generous of you to offer advice to those seeking greater performance from their recreational outboards.<br /><br />Please share that advice with all of our members. Those seeking advice can just as well post here as Email you. Then all can learn, not just one.<br /><br />I, for one, would like to learn how to maximize horsepower without compromizing reliability. In 50 years of messing about with recreational and racing, air and water cooled, 2 stroke engines I have found those characteristics incompatible past a certain point.<br /><br />Thanks again for your offer. :)
 
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sinkingfast

Seaman Apprentice
Joined
Dec 31, 2003
Messages
34
Re: two stroke motors

No problems, although I can write a rule of thumb to allow members to read their engines first.<br />Reading is the main point to tuning. it tells you which way to go and why.<br /><br />You can waste so much money tuning and engine that is running at 85% and get to an increase of 15% on that, when for no money, just correct settings , you can run at the 100% that the engine was designed for without reliability problems.... its what the engine was designed to do in the first place.<br /><br />There is no reason to start altering , replacing components when all the average guy wants to have is an engine working to 100% of its efficiency and therefore reliable.<br /><br />JB email me and let me see which way you look at the problems and I will see if I can steer you<br />Geraint :p
 
WillyBWright

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: two stroke motors

BLESS YOU!<br /><br />Finally, somebody that agrees that the Best Way to get the most out of your motor is to keep it properly tuned to Factory Specs. A lot of "tweaking" leads to a lot of premature failure, and little or no improvement in performance. In fact, it frequently Decreases the performance And the motor's life expectancy.<br /><br />Factories spend a lot and money and time getting the most power they can while keeping the motor as reliable as possible. We as mechanics or owners couldn't come close to that, even collectively. With us, it's hit-or-miss at best...mostly miss, at least down the road. I wish more people would realize that.<br /><br />Competetion between the manufacturers guarantees the best power and the best reliability. Who in their right mind would buy a poor performer that fails frequently over a good performer that lasts and lasts??? Ain't Competetive Capitalism a wonderful thing? If a manufacturer is to survive, performance and reliability must coexist. "Tweaking" is at our own peril, and the ones that suffer the worst are usually the boat owners that wanted "more".<br /><br />God Bless the Queen.
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: two stroke motors

Hi, Geraint.<br /><br />I would prefer to share my questions and your advice with our members. That way you are less likely to get the same questions over and over.<br /><br />I think I misunderstood your statement about max hp without compromising reliability to refer to highly modified engines, rather than to getting the designed performance from an unmodified engine.<br /><br />My comment referred to engine and fuel modifications (or substitutions) that increase torque and peak rpm but typically shorten the life of the engine. A racing engine that lasted to the flag was reliable in my mind, but a recreational engine has to last into the thousands of hours of WOT operation to meet my definition of reliable.<br /><br />I will be very interested in your methods of optimizing performance of unmodified engines. :)
 
S

sinkingfast

Seaman Apprentice
Joined
Dec 31, 2003
Messages
34
Re: two stroke motors

some of our racing engines have to withstand 16,000 rpm and hold 14,500 for quite long periods.<br /><br />I recon the average guy wants a motor that works, works well, keeps working and stays in one piece.<br />But to get the best from the motor, the settings will be altered from the base settings ...... oil burn, fuel/oil burn, fuel burn and climatic factors can lead to motors producing some 10 to 20% more torque from standard motors in standard trim, before johnny tuner starts getting his files out.<br />Think about it..... why have it set to hold performance back.<br /><br />I guess I will have to do an article for the board<br />although I would like some input from a typical motor user so I can see the way the boaties attack the problem before I write..... hence the request to email direct...<br />In the mean time can somebody tell me if you guys scope your piston crowns and read the burn?
 
JasonJ

JasonJ

Rear Admiral
Joined
Aug 20, 2001
Messages
4,163
Re: two stroke motors

I too would be interested in info, but I hope you remember that the vast majority of us just walk out, put gas & oil in, turn the key and go. There aren't a lot of us that rip our motor apart every other weekend, or are willing to have our motor out of commission for too long of a time. My boating season only lasts from late April to beginning of October. I put the boat in the water, it stays in the water, and comes out when the season is done. I do any work thats needs to be done in the off season. If you have tips for someone like me, things I can do with my boat sitting down on my dock, that would be cool. I do the typical maintenance, checking and cleaning plugs, that sort of thing. I do know my way around an engine, so thats not an issue, but I, like so many of us here, am so happy the thing runs that we almost don't want to touch it for fear our tweeking will make it unreliable. Thanx for wanting to share the info...<br /><br />Scope the piston crowns to read the burn? If it starts and runs all day, thats what I look for. I do like the thought of more efficiency.
 
OBJ

OBJ

Supreme Mariner
Joined
Dec 27, 2002
Messages
10,161
Re: two stroke motors

I think it's also important to realize that what wrenches deal with are production line engines. They are tuned to perform in more than condition of altitude, climatic factors and the like. You could tune in an engine for around the home front but what happens to the engine if you take it south or further north in the higher altitudes or warmer/colder climates? Performance goes out the window? Most folks that travel for boating different waters need this all around tuning we get from the manufactuerers.
 
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Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: two stroke motors

I have scoped the piston to read the burn. Usually done when jetting carburetors. It's usually done with a high speed chop and then examining the intake side of the pistons for amount of wetness. <br />What's your procedure and bases for conclusions?<br /><br />c/6<br />Hooty
 
S

sinkingfast

Seaman Apprentice
Joined
Dec 31, 2003
Messages
34
Re: two stroke motors

Gotcha.<br /><br />Ok guys we are all talking the same language.<br /><br />I will come up with as many basic factors over the next few days as I can to establish baselines.<br />Some might be so obvious to be as read but I am sure you will find several that will suprise you.<br />I am aiming at the average guy, average use, average motor who wants to run his standard motor and know its right... 100% right and simple rules will keep him 100% right and prolonge the life of his motor 5 fold.<br />Hopefully all it will cost is a slight change in routine and bad habits, a few small adjustments and many years of faithful service from a happier motor..... ( and owner )<br />I can keep it simple or as complex as you guys like....... are we on?
 
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Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: two stroke motors

Roger that.<br />Let's see whacha do.<br /><br />c/6<br />Hooty
 
A

Andrew Leigh

Chief Petty Officer
Joined
Jun 17, 2003
Messages
431
Re: two stroke motors

Can't wait.<br /><br />Cheers<br />Andrew<br /><br />PS: Your boys did good in RWC 2003.
 
M

Mettaree

Petty Officer 1st Class
Joined
May 17, 2003
Messages
292
Re: two stroke motors

geraint:<br />Bring it on - always want to learn<br />Jim
 
M

mellowyellow

Vice Admiral
Joined
Jun 8, 2002
Messages
5,327
Re: two stroke motors

OK, I'll bite. 1970 merc 1150 I6. have seen many<br />suggestions to retard timing etc. your thoughts?<br />regards,<br />M.Y.
 
S

sinkingfast

Seaman Apprentice
Joined
Dec 31, 2003
Messages
34
Re: two stroke motors

instalment 2 on the way.<br /><br />Aimed at the novice and semi spanner happy.<br /><br />Should raise a comment or two :D
 
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