hole shot problem

[MIKEY*2007]

I have old 68 100 hp merc on 17 ft p/ wood when I try to pull a big or heavy skier she bogs down just enough to drag them for a bit making it hard for learners to get up is there a different prop I could use from the standard one to give me more of a get up and go as motor runs perfect not worried about top end speed and don,t want to over rev motor,thanks in advance mike

 

[Irv964]

Re: hole shot problem

Post this in the prop section but before you do we need some numbers.
What is your current max rpm and speed? What is the max rpm that your motor is rated for? What size prop and pitch do you currently have on there?
Where is your cav plate in relation to the bottom of the boat?
Also, how many people, extra weight etc are you carrying while skiing? ........Irv964

 

[kenmyfam]

Re: hole shot problem

Before you consider a prop change make sure your set up is at it's best. Weight distribution on the boat, motor height and trim angle. Then consider a different prop from there. What prop are you currently running ????

 

[kenmyfam]

Re: hole shot problem

Post this in the prop section but before you do we need some numbers.
What is your current max rpm and speed? What is the max rpm that your motor is rated for? What size prop and pitch do you currently have on there?
Where is your cav plate in relation to the bottom of the boat?
Also, how many people, extra weight etc are you carrying while skiing? ........Irv964

I guess we were typing at the same time eh !!!!

 

[MIKEY*2007]

Re: hole shot problem

sorry boys for late reply computer problems ,boat is trimed and set up fine runs at 35 mph or 70 kph here in oz, just me and ouvserver prop is a standard from new as also my spare is off the same model motor although my boat is a deep vee for offshore fishing Idon,t think that should have any bearing on the matter I don,t know what angle or pitch is except it is standard

 

[tashasdaddy]

Re: hole shot problem

get the number of the prop, then you can tell what you have. going higher in pitch, give you possibly higher wot speed. going lower in pitch give you more power getting out of the hole, but you could loose a little on top end speed.

we used to call them in the old days, speed props, and power props. also check the compression on your motor, could show a problem.

 

[MIKEY*2007]

Re: hole shot problem

ok prop is 13 " dia pitch is 21" 3blade alumium revs at 5500 rpm witch is in range of manual. does have wot speed more than old identical motor, psi is 140 on all cly as previous owner had rebuilded thanks mike

 

[j_martin]

Re: hole shot problem

The difference in hole shot between that screw and a 4 or five blade stainless ventilated prop would be astonishing. (20 in High Five)

Ain't cheap, though.

How does it act when you take off? Does it spool up a little and pull hard, or is it "bogging"? Maybe just putting some ventilation holes in your present prop would help quite a bit. (cheap)

hope it helps
John

 

[CharlieB]

Re: hole shot problem

A very slightly lean idle mixture can cause less acceleration when pulling up a skier or a tube, yet not be noticable on a more 'normal' hole shot.

Easy enough to try, back out all idle mixture screws 1/8 turn to see if any improvement. If yes, try another 1/8 turn, and so on, until it no longer improves .

Dial in idle mixture before venting your prop to get peak power from the engine.

THEN Venting the prop will make a VERY noticable improvement.

 

[tashasdaddy]

Re: hole shot problem

actually dropping to a 13x19 will make a big difference for hole shot. 21 is too high for pulling a skier. you will loose a little top end, but not much.

 

[kenmyfam]

Re: hole shot problem

actually dropping to a 13x19 will make a big difference for hole shot. 21 is too high for pulling a skier. you will loose a little top end, but not much.

Agreed. Give a little in top end but gain a lot on hole shot. Your skiers will love you for it.
Having said that is the set up good ????

 

[MIKEY*2007]

Re: hole shot problem

thanks for all your input guys, late reply having wows with computer sorry. went with 19 " pitch unreal!!!!! ripping there arms off speed loss hardly noticeable, now does anyone know how to get skiers to help pay for fuel cost?

 

[Maclin]

Re: hole shot problem

Don't give their arms back until they pay....

 

[MIKEY*2007]

Re: hole shot problem

love it.

 

[kenmyfam]

Re: hole shot problem

thanks for all your input guys, late reply having wows with computer sorry. went with 19 " pitch unreal!!!!! ripping there arms off speed loss hardly noticeable, now does anyone know how to get skiers to help pay for fuel cost?

Get them to leave their wallets on board while they ski for safekeeping, take them a few miles out and give them the "swim back" option if they are not willing to contribute !!!