dang ol hydrofoil!!!!!!!!!!!!!

[longdude17]

I have a 89' mercury 35 on a 15 foot bassmaster bass boat, and I am having wot rpm trouble. I am pulling 3200 to 3400 rpms at full throttle. this cant be right. I have a stingray hydrofoil on it and was wondering if it was the culprit. shouldnt I be turning 5500 rpms? carbs have been cleaned and tuned. and its just me in the boat. What is the deal! Just got the boat and dont know what to try. I have the motor trimmed up when at wot and still only 3400 rpms!!!! what to do !!!! thanks for looking.<br /><br /> Dustin

 

[NathanY]

Re: dang ol hydrofoil!!!!!!!!!!!!!

Are you sure that you are not over propped? Check where the AV plate on the motor is in relation to the bottom of the boat. I like to run mine about 1/2 inch below the bottom of the hull. Hydrofoils are designed to raise the bow of the the boat up, so, unless it is improperly installed, I dont think that is the problem.

 

[Hooty]

Re: dang ol hydrofoil!!!!!!!!!!!!!

I don't think you're hitting on all cylinders. What happens if you bump the choke or sqeeze the priming bulb? <br /><br />c/6<br /><br />Hooty

 

[buttonhook]

Re: dang ol hydrofoil!!!!!!!!!!!!!

check the carb they may be dirty,<br /><br />sorry I didn't read it all! you said you cleaned them.<br />may still have something in there.<br /> I engine was sucking pieces of the foam in from inside the engine hood. I'd clean it, run it and then it would start to fall off again. I like to never figured that one out.

 

[buttonhook]

Re: dang ol hydrofoil!!!!!!!!!!!!!

also make sure the vent it open on your gas tank!! very simple but I've missed that one before to. can make you engine run like that as it starves it for fuel.

 

[RICKRICK1]

Re: dang ol hydrofoil!!!!!!!!!!!!!

Did you do a link and synk after you cleaned the carbs? Are the butterfly valves opening up all the way at WOT?.

 

[longdude17]

Re: dang ol hydrofoil!!!!!!!!!!!!!

thanks for the info!!! I had the carbs rechecked by a proffesional and he said everything was set to specs. I tried it again and still the same. I then commenced to clean the carbs again, and run it with the tank vent open and with the hood off and still the same results. I am guessing its over propped. I will check to see if I am, but does any one know the rpms that it should be turning? I will also check to see if my motor is too low in the water. but everything is factory settings, factory prop, and the factory put the motor on. does any one else have any good Ideas?

 

[buttonhook]

Re: dang ol hydrofoil!!!!!!!!!!!!!

is your tach set right??

 

[longdude17]

Re: dang ol hydrofoil!!!!!!!!!!!!!

its set to the factory specs, i think, how can you tell if its set right?<br /><br /> Dustin

 

[buttonhook]

Re: dang ol hydrofoil!!!!!!!!!!!!!

get a tiny tach (there fairly cheap less than an hour at the shop) and put on it compare the two. if your number jive it's not you problem if they don't well then you know something is a miss.

 

[longdude17]

Re: dang ol hydrofoil!!!!!!!!!!!!!

before I go get any of this ( it is a good Idea though!) I was wondering if any of you brilliant mathematician boat mechanics could tell me the appropriate prop pich and size for this motor and boat and weight? This will help me eliminate the burden on my mind about it being over pitched. thanks again <br /><br /> Dustin

 

[longdude17]

Re: dang ol hydrofoil!!!!!!!!!!!!!

what about a jack plate would that help? <br /><br /> Dustin

 

[Boatin Bob]

Re: dang ol hydrofoil!!!!!!!!!!!!!

There are several web sites out there (this is just one example) that have prop calculators, give it a try and see what it spits out in comparison to what you have on there now. Prop Calculator