yamaha 70 ces

[Hounddog]

how can i gets a copy of them 90hp specs Hounddog ?

Fred, since Hydro Tec is in the engine building business they likely wouldn't give you the spec sheet unless they did the work. I think they have the only copy. I know several other guys got more horsepower, Steve Cooler for one. He was in the 130 hp range as I recall, but did have issues with blowing head gaskets. Popa Sam can build a mean 90 for sure.

Just to get back to the original thread. A racer e-mailed me askng me why having 200 lbs compression as a problem. It makes power!
My answer is: It will get you more power off the dock. It hurts you top end wise because the motor is actually fighting itself because of the added compression at the high RPM, so it slows you down. It also results in a much shorter engine life, especially if you running stock parts. It is one reason why the Yamahas break a lot of parts. It is also why I find it difficult to believe you can get 200 lbs compression legally in a stock 70 CES and if you could, It would slow you down. Again just my opinion.

[lcp]

hounddog, any idea how can i keep in touch with steve cooler?regard Mr Lo.

[Carl Kinder]

I would just like to stop the thinking!! that the Yam 70 is a weak engine if you carry out any work to the engine. This is not true. We race every Thursday evening (20 weeks) plus a National series plus World series !!. Rouen the engines race for 24 hours ! and the same engines are still racing several years later having covered many 24hour races.
The biggest problem is the engine is getting old !.
Old engines dont die, they just get moved on !!
In 1990 Yamaha changed the spec of the Yam 70ces (modified cyl head, 2 ring pistons,carbon reeds etc)
Some original engines had update kits fitted, some are still racing now.
Enforcement of UIM rules has had its ups and downs over the years !. So you find several different levels of legal !!!!!!!!, depending on when the engine was raced.

The fastest and most reliable engines in the World championships are to UIM spec.

On a tunnel boat its a big difference between a engine made to UIM spec and a out of the box motor (speed, not reliability)
In the 25 plus years this engine has raced most things have been tried.

Old engines never die, they just get moved on !!!!

[Fastjeff57]

Just curious, but how flow effective are the stock reed systems in 70 hp Yamahas? I adapted a set of them on my Merc triple and--though they look kinda small--I assume they must flow pretty well for these motors to perform that well. (The same reeds are used for the 90 hp Yamaha, by the way.)

Jeff

[Hounddog]

hounddog, any idea how can i keep in touch with steve cooler?regard Mr Lo.

Sorry, I can't help you. I know he sold his FV 90 yamaha to Ernie Brown and I believe Erinie sold it to a fellow on this site. It was a green SSV hull number 27 if my memory is right.

[Fast Fred]

well lets see, never did lose the press on a 40-50 hp yamaha cranks, no matter how bad it was beat on, you can stuff it at 8000 , if you don't empty the foot she will just keeps goin.
maybe thats not a good comparison , could look at the Stinger, not known to lose her press.

anyway the Factory puts a ton of R&D in, not to mention we can see the history of how that info performed, port maps like the 19-s, the 60DES, SST60, they have value cuzz they are tryed and true, you know it worked, time after time, record after record .

so check this, " i have a port map for sale" ,,,, or,,, "i have a port map for sale, it has the Kilo record, and the marathon record " witch one you guna pay for. that is not to say the first port map offered was not the same or better.

oh, until they start given away free samples at the bank, i expect to have to pay. not sure if that was a Question in there.

185psi seems to be the number Hounddog.

[Hounddog]

To get right back to the original post and offer the fellow some suggestions:
Since you do not know the history of that motor, do the basic initial checks
- clean the carbs
- check the reeds for damage
- re do the fuel pump and check the fuel lines
- drain and check the lower unit
- replace the water pump
- look inside and mid and check the tuner... is it complete?
- put fresh fuel in and flush out the fuel lines
- start it up.... how does it sound..is it smooth?
- check the compression is it in the 150 to 180 range, are all cylinders equal?
- go out and test it. If it turns the props you have in the 7500 range...
LEAVE IT AS IS!

[Fast Fred]

thinkin theres a new set of plugs in that spring make reddy list, maybe wave the grease gun at it,

[mobil1]

Have already done all the things in the list, only not checked the tuner...
But i took a sneak peak in the cilinders before i bought it, togheter wit the compression test. An i could see the marks of honing in the bores.
So the engine doesn't have that much run hours
Replaced the plugs by iridium ones,
Drove her once, with a to small prop, everything was ok.
Wheater has been to bad to test the cleaver.

All i asked was a little bit of info from these engines so i can check if the engine is mod...
And some info from the problems i could encounter trying to fit the 90hp carbs that i have laying arround from a blown engine...
If i have them, why not use them...
Technical aspect is not a problem, i am a technician...
And see ALOT of tuning on both s3000/F1 and the sterndrives.
So if i ever feel the need to do some porting and others, that won't be any problem.

grt

[Fast Fred]

there is two styles of 90hp carbs, the square style fit right on, the round style you need to change the screws in the top of number 2 and 3, number 3 needs some room between the tray and the bowl, if you don't want cut the tray, you can sand off the bowl and just get it.
i liked the round style best.