zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

[roverpete]

Hey everybody

I have a new typhoon 360s with a Suzuki 15hp 4stroke EFI engine. with three adults on board at WOT throttle It hits the rev limiter. I was wondering if the stock prop may be to high pitch for this light of boat. I don't have an RPM gauge to see where this is occurring. Anybody else have similar problem with ther SIB or RIB that was resolved by bumping up the prop pitch?

 

[fbpooler]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

High pitch lowers RPM, so you need a higher pitch to decrease to recommended range.

 

[Sea Rider]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

Most portable engines delivered with standard factory props usually produces near full, full and in some cases over revs, in 4 strokes engines it's good to have a rev limiter, sadly not found on 2 strokes portable. A induction Hardline or TT tach is a must buy, will keep track of worked hours too, With current set up and load throttle to 3/4, if limiter doesn't kick in throttle more in small increments untill limiter kicks, check how much throttle is left available.

In your particular case, it's a wild guess which would be the correct prop pitch to choose, unless you have the factory specs to check at which max rpm the limiter is kicking in. That way can play with prop pitches some numbers up ( more pitch) to pull revs down into max safe working engine parameters.

The factory delivered prop is useless at this point, rev limiter kicks in with 3, imagine solo boating with just you, rev limiter will kick in much earlier with less throttle.

Happy Boating.

 

[deejaycee_2000]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

Are you sure you're not mistaking it for cavitation? I somehow doubt a 15hp will hit rev limiter pushing 3 adults unless the prop is out the water ....

 

[Sea Rider]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

Unless engine sits too high on transon and experimenting aireation (prop works near sea level) you could have a spun prop...

Happy Boating

 

[roverpete]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

Looks like it was pitch problem. I bought 4 blade prop 9.25 x 10 and the boat zips along at 23mph and no over revving. The motor is as low as the transom will alow.

 

[Sea Rider]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

Before venturing buying and playing with prop pitches, you should check proper leg/transom height match. All boats are not being factory delivered with same transom height nor tube diameter. And engines doesn't have same lenght distances from small upper deflector plate to anticav plate neither, which can vary from brand to brand. What's your top wot reading with new prop ?

Happy Boating

 

[azzurro]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

Maybe not the same problem, but I hit the rev limiter when jumping waves. Obviously the prop works in the air.
Then wifey complains abot jumping and panics because I have to start the engine.

 

[fbpooler]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

You mean your engine is not fitted with a left hand widget to slow the engine when it is not working against a load? It would tell the engine the prop was not in water and slow the engine speed plus preventing the water pump from running dry.

 

[Sea Rider]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

You mean your engine is not fitted with a left hand widget to slow the engine when it is not working against a load?

Just curious, which engine brand and model uses that neat tech system ?

Happy Boating

 

[fbpooler]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

Hasn't been invented yet, so a hand on the throttle has to do if jumping waves. It is hard on an engine, prop, and drive train if a motor is allowed to lose purchase on the water while hot dogging and suddenly be put back under load when the lower unit reenters the water..

Check the smiley at the end of the post to see how serious I was

 

[Sea Rider]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

Yep, you made me laugh and doubt for a while, was about to say that this out of this world neat tech system was only found on larger engines. Will need to ask the guys that races zap cats how do they handle this issue, asume being larger engines, the rev limiter will kick in and cut the engine's excess rpm down till w?ter re entry.

Happy Boating

 

[fbpooler]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

I think the rev limiter was a wonderful invention, as they did not have them when we started playing with outboards. Running off shore in 20 ft range boats, sometimes we hit the proper waves to pull the motor clear of the water from time to time which always made me sweat big time. That cost me a prop hub offshore once which was a real problem, but thankfully we were able to limp home carefully with low speed.

I watch these folks on YouTube sometimes who seem to be having a great time jumping waves. You have to wonder if they understand just how much shock force the transom, motor and drive train have to handle under those conditions. Horizontal splits in the transom of offshore boats are not unusual.

 

[deejaycee_2000]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

Yes we have to work the throttle all the time when jumping waves otherwise you can either over rev it or spin the hub .... we do not have rev limiters

Yep, you made me laugh and doubt for a while, was about to say that this out of this world neat tech system was only found on larger engines. Will need to ask the guys that races zap cats how do they handle this issue, asume being larger engines, the rev limiter will kick in and cut the engine's excess rpm down till w?ter re entry.

Happy Boating

 

[Sea Rider]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

Hi Deejaycee,

Was wondering how do you tune zap cats, are you matching a prop that gives around or slight passsing middle rpm wot parameters for good hole shot, or you run full wot rpm props for top speed.

Happy Boating

 

[deejaycee_2000]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

I use to have about 5 different props, all very much different depending on the weather or kind of weather we have to race in at a specific time ... but we pretty much go WOT all the time ... on circuit racing we use either lower pitch props for quick hole shot and on the longhual bigger pitch for top speed ... the water can get very rough at times so a semi cleaver like the 15G Yamaha prop works nicely, otherwise a Merc vengeance for calmer waters runs like it is on fire, longhaul we run anything form 16p to 19p depending on the weather ... I normally push around 6500rpm at WOT, some of the modified guys push 10000 rpm easily...

 

[fbpooler]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

That is something else to get that kind of performance. I am too old to run a boat like that, but it is really interesting to see what you fellows can do.

Those engines must be balanced to some fine degree to withstand RPM like that.

 

[Sea Rider]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

Probably using titanium crankshafts & rods or any other out of this world materials. Does Tohatsu have a racing dept as Merc has ?

Happy Boating

 

[deejaycee_2000]

Re: zodiac typhoon suzuki 15hp 4 stroke hitting rev limiter?

We only race with Yamaha and Tohatsu motors as they are the only motors homologated for our class of racing .... the crankshafts gets perfectly balanced and pinned or welded ... the engine mounting gets strengthened, head shaved, all blueprinted exactly to factory spec ... it's alot of fun!