The Yamaha 40 hp and 30 hp Midrange four strokes are known for their small size and solid performance. Light and powerful, these nimble, three-cylinder wonders are perfect for light duty on skiffs, jons and inflatables and small pontoons or aluminum fishing boats. With single-overhead camshafts and electronic fuel injection, they deliver quick starts, responsive power, quiet operation and valuable efficiency.
The Yamaha Midrange and hp four strokes. Reliable power for any small-scale, boating application. Precision Multi-Point Electronic Fuel Injection delivers the exact amount of fuel needed for optimum performance and efficiency.
All air entering the engine block of is routed through a single throttle valve, to ensure the precise amount of air necessary for optimum power and fuel efficiency.
YAMAHA PROPELLER SELECTOR
It then enters each cylinder through individual long intake tracks, which are 'pulse tuned' to provide air at the precise volume and timing for maximum density and power. The F40 and F30 feature a vapor-reducing fuel return system. Used in conjuction with multi-point electronic fuel injection, they offer dependable turn-key starting in hot or cold conditions. This protection is standard on all Yamaha Midrange four-stroke engines. The nimble, responsive F40 and F30 offer more than incredible performance.
They also offer the option of variable trolling capability.
With its single throttle valve, long-track intake manifold and electronic control module, it delivers easy starts, fast acceleration and excellent top-end speed. Our cc hp midrange boasts a streamlined design and solid performance. Its Nitro Assist Tilt makes tilting almost effortless. All Jet model weights include the jet pump assembly weight estimated.
30 HP Yamaha OEM Outboard Parts
Midrange Four Strokes Mechanical or Tiller: 40 hp, 30 hp. Owners Manuals. View the 40 hp. Fuel Economy. Fuel Economy Precision Multi-Point Electronic Fuel Injection delivers the exact amount of fuel needed for optimum performance and efficiency. Single Overhead Camshaft. Precise Throttle Control. Precise Throttle Control All air entering the engine block of is routed through a single throttle valve, to ensure the precise amount of air necessary for optimum power and fuel efficiency.
Dependable Starting. Dependable Starting The F40 and F30 feature a vapor-reducing fuel return system. Product Videos:. Expand Gallery. Meet the Line-Up. Switch Panels. Prop Selector.What [must be] changed? Although not too many boaters look at changing [carburetors] as something they could do at home. As there are probably more boaters that would rather take their outboard in for a new water pump impeller, than do the easy job themselves. My thought is [carburetors] may be different, or just jets.
Possibly a different exhaust tuning plate.
Electronics limiting spark advance or different module. Were only talking about a HP difference. I have done this with a Optimax to plug n' play. I have a model year and after purchasing a replacement parts manual from Mercury, which covered both the 75 and 90, I concluded that the only difference was the high speed jets and the timing advance.
I would love to see you give it a try and report the results. I just haven't had the time. High speed jets. What did Mercury use to control the timing advance? A different Module?? Thanks, Russ. The old fashion way. The easiest outboard to "hop up" is the OMC It was made in hp configurations.
Some are through prop exhaust and the lower HP are not. I don't think that just swapping out the carbs would do much except consume more fuel unless the timing is also changed.
The I was only mentioning motors with through the prop exhaust.
Mid Range Four Stroke 30 - 90HP
You will find that with the 35hp carb all sizes run the same. You might have to browse through 17 or more pages. Most modern motors are run by electronic controllers which define their power output.
The easiest way to get more horsepower is to travel by boat to a remote island with a group of the factory engineers from your engine manufacturer, drink rum with them for three days, and cajole them into loading the new firmware into your engine controller. They've been available for computer controlled gas engines as well as diesel trucks for a long time. A chip or a custom PCM flash cannot lift a valve higher, or hold it open longer, or make the cross sectional area of a cylinder head port or exhaust manifold larger.
IOW, it cannot remove mechanical restrictions. Thus, when installed on a normally aspirated car all it can do is to make the spark timing tables more aggressive, or the WOT fuel tables a little leaner, which is usually good for a handful of horsepower at the most.
And it comes at a cost. The oem PCM calibration engineers usually make the fuel and spark tables reasonably conservative in order to protect the engine in hard use. Now, if it is a turbo motor with a computer controlled wastegate, and the turbo is sized with some extra capacity, you can through a custom tune, have the turbo put out considerably more boost than it does while stock.I have heard from several people that there is absolutely no difference in power between these motors.
I am almost certain that this is true at the low end and mid range, but I am curious about the top end. Given the ten-percent leeway that manufacturers are allowed on power ratings, the 25 could be as much as It is entirely possible that they make the same power and still meet the rating requirement.
I would be willing to spend this if I really thought I was getting something for the money. I notice that Evinrude does not publish any performance reports on the 25 and 30 where the motors are run on the same boat. I don't usually go in for conspiracy theories, but I have to admit that this does make me a bit suspicious. Anybody with any thoughts or experience with this? Your 30 hp will come in handy with any extra weight in the boat or if your kids want to ski or tow a tube.
If the money is not the issue I would not think twice about it. I feel that a 30 hp is the best all round engine for a 13 whaler If you get the 25 and it is not up to snuff you will regret not getting the It is probably just a bit of ECM mapping. Problem might not be the 5hp, it is most likely prop choices.
I just wanted to see if I could find some way to get a direct comparison of the 2 motors on the same boat. What is the basis for this assumption?
There is a ten-percent manufacturing tolerance permitted. Any particular engine coming off the assembly line coulhd vary from the rated power by as much as ten-percent. There are constraints on the rated power, but only that the rated power is recommended to be within six-percent of the peak power that occurs in the recommended operating range. Horsepower is often proportional to engine speed, so a higher engine speed produces more peak horsepower.
You will not see much difference in the engines until you are in the upper portion of the engine speed range.YAMAHA 30 HP 1998 old start after 2 year storage
We had a thread started a while back that asked specifically what could be done through the ECM besides rpmto cause different horsepower ratings in otherwise identical motors Some interesting ideas were kicked around though, like intentional misfirings, spaced in such a way as to be undetectable. That is exactly what has me puzzled.Login to Your Account.
Remember Me? Results 1 to 8 of 8. Thread: servicing 30hp yamaha 2 stroke. Thread Tools Show Printable Version. Re: servicing 30hp yamaha 2 stroke Impellor?
Clean the carbies. The list goes on.
No airfilters. Re: servicing 30hp yamaha 2 stroke thanks mate i just need to buy a torque wench now. Re: servicing 30hp yamaha 2 stroke The impeller is a component of the water pump that gets water round your engine, it is made of rubber and degrades. The impeller needs to be replaced on a regular basis. I suggest you grab the service manual for your outboard and have a good read, pick a digital version up on ebay or readmanual. Re: servicing 30hp yamaha 2 stroke Like the others have said the impeller is vital, without a healthy one the rest of the engine could end up being a over sized mantle piece.
Re: servicing 30hp yamaha 2 stroke ok thanks guys i will replace this impeller. Re: servicing 30hp yamaha 2 stroke I just do mine every spring,but very much worthwhile to give her a run regularly even on the muffs.
But certainly pulling your plug occasionally will give you a good idea on how its running ie rich,lean. Re: servicing 30hp yamaha 2 stroke. Every year or as per the manual if you do more hours than WD40 can affect the rubber on plug leadselectrics and cowl and leaves them greasy.
There is special under cowl sprays and just rinsing with warm soapy water gets rid of the salt crystals.
Yamaha Marine Parts Finder
Some people use teh lanoline based ones Remove the prop and check behind it for fishing line and any seal damageregrease spline shaft and replace prop. Grease pivot points, linkages. Annodes should be removedcleaned and replaced if erroded significantly. Seriously look in your manual or download one which will show you all teh jobs to do on minor annual services. If it is a 2 stroke it may be worth doing a decarb once a season depending on what quality oils and fuels you use.
Nothing is real hard to do but it is all worth doing properly and well worth the one off expense of the service manual to get it all right. Plenty easy to stuff it up if you haven;t seen it done befpre or aren't good on teh tools.
IF you have amate who is good on teh tools and experienced in outboards get him to show you teh ropes or if local to a decent mechanic pay himand watch so you pick it up gradually. Join us. The time now is PM.Login or Sign Up. Posts Latest Activity. Page of 2. Filtered by:. Previous 1 2 template Next. I have heard these little 25's are sleeping giants and I am trying to unleash the beast within mine!
I have purchased both the performance head kit and the exhaust tuner kit, plus I have downloaded the service manual. The head replacement seems pretty straight forward but the exhaust tuner installation is stumping me.
Is it possible to install the exhaust by removing the lower unit and then dropping the upper case? I tried but could not get the upper case to break loose. I did not get too aggressive with this for fear of damaging something. I am not the most knowledgeable on outboards but it looked like this was an option looking at the exploded diagrams.
If this method is not an option I am going to have to bring it to the shop because I would not be willing to go in from the top side, way more than I am willing to tackle. Thanks for any insight. Tags: None. Last edited by 99yam40 ;AM. Comment Post Cancel. Well that's what I was afraid of, thank you for the info. And to answer your question about upsizing the hp, I fish in a refuge and they cap the motor size at 25hp. Thats a expensive mod for sure That kits are expensive at least for my pocket but I understand you may not have other option You're right it has gotten a little pricey just ask my wife, lol but I have been saving for some time now.
I do intend on increasing the jets because I also have Yamaha 40 carbs to install on it too. The manufacturer of the performance heads informed me that if I install the heads that I would have to at least bore out my existing jets. Hopefully I will not be the last boat to the fishing hole anymore!! Thats the type of things that my wife doesn't need to know the price lol 25 main jets are 96 and 30 are 25 slow jets are 54 and 30 are 50 The only diference between these 2 motors are these 6 jets 30 main jet part 6JE 30 slow jet part 6JF The yamaha 40 carbs will do but you'll need to make even more mods With Yamaha 40 carbs you'll need a fuel pump while Tohatsu carbs have fuel pump attached like you carbs On Yamaha 40 the mid carb have diferent main jet size from top and bottom carb while tohatsu have all 3 main jets the same size like you motor Tohatsu main jets But YES, Yamaha carbs will do Boyesen reeds B may be something to consider if you have money to spend on this project I never use them but I'm sure will not give you more power like a few claim, just a better response while accelerating If you'll do all this mods be prepared to spend more money on a big pitch prop After all with money of the sale of your motor plus money spent on mods you could get a good 2nd hand 40 or 50 HP but if you have that restriction and like to have a project on hands go ahead I have that model but with 30HP and its a great machine!
Good luck. Last edited by almetelo ;AM. So let me make sure I follow what you are sayingUpgrading to a Chain conversion with an X-Ring type chain can be easy on the wallet and mechanically straight forward. It is abasic modfor all ranges of skill in the garage. With a torque wrench, chain splitter, and a basic set of tools you should be able to swap the stock setup for the new gear in about 30 minutes depending on your skill level, some can turn this into a four hour job.
You willalso needto purchase a speedohealer in order compensate for the change in gearing. What does the chain conversion and new X-Ring chain do for you? It does give you asignificant increase in torque. More importantly the lighter sprockets weigh less and the X-Ring chain has lower friction which gives youtwo things.
If you change the gearing down then you will get more bottom end drive from low speed and vice versa if you gear up you get more top speed.
By using the Gearing Commander you can figure out exactly the combination you desire for your particular riding. If you need more power out of the corners or need that extra MPH on the top end this is the mod you have been looking for. Not exactly a30 Hp increase but it sure can feel like it if you gear it down a couple sprocket teeth! Jump to. Sections of this page.
Accessibility help. Join or log in to Facebook. Email or phone. Forgotten account? Sign Up. Yamaha r6. All Notes. Embed Post.Remember Me? Results 1 to 5 of 5. Thread: Yamaha 30 2-stroke mods?
Yamaha 30 2-stroke mods? Hey guys, Just purchased a 2 stroke 3 cyl Yamaha 30 HP and I understand there are some performance mods that can be done on these motors to gain additional HP. Can somebody steer me in the right direction as to what mods are gonna give me the most bang for my buck and that I can do myself at home without having to do any machining i. Compression readings at last service were PSI and for now, the motor is pushing a Lowe, although I may put it on a slightly bigger hull if I can find one that I like.
You can fit carbon reeds from CCM or boyesen. Above prop exhaust mod, again worth having a read about before hand. I would say it's worth shaving the head if you can, shouldn't cost too much to get done. Either way you can get better spark plugs, with standard head you could get slightly longer ones, same as they do on tohatsu 50's.
How much of this stuff do you think I could reasonably do myself? I have never worked on an outboard engine before and don't know a lot about them. I used to do simple car repairs before everything became electronic and you had to have special diagnostic equipment to even figure out the problem.
I guess what I'm saying is I'm not completely mechanically uninclined but I'm not an outboard mechanic either. You could do it all yourself, I learned on outboards. Doing it is the easy bit, knowing what to do is the hard bit, just read up as much as you can before hand. Know of anyplace that has "instructions" rather than suggestions? I did a search through the forums here and found several posts offering a multitude of things that could be done.
Replies: 1 Last Post:AM. Replies: 1 Last Post:PM. Replies: 0 Last Post:PM. Replies: 3 Last Post:PM. Bookmarks Bookmarks Digg del. All times are GMT The time now is AM. All rights reserved. Boat Racing Facts Copyright to