SIB not planing

[rivrunner]

Hi Mike....thks for the thought.....checked the prop and it's in very sturdy and neither i or the previous owner ever hit anything

[Poly]

Originally Posted by rivrunner

Hi Mike....thks for the thought.....checked the prop and it's in very sturdy and neither i or the previous owner ever hit anything

Well the previous owners says that! Even catching it on a rope can sometimes be enough. If the previous owner is around can he shed any light on your issues?

My guess is you have a fuel problem so not developing max power (dirty carb, blocked filter etc). Accurate diagnosis is impossible without more info. I'd suggest getting a TinyTach (or copy on ebay for a tenner) because: 1. it will help you identify the problem, 2. it will be useful in the future, 3. it will help you select the best prop in the future, 4. keeping an eye on running hours is useful, as can tracking trends on revs.

I wouldn't rule out the prop slipping on the bush, although I think its not the most obvious issue. You can't usually spin it easily by hand - make a mark with something like tipex covering both the prop and the shaft/nut. Take it for a run and then see if the lines still match up perfectly.

[Last Tango]

Can you post a photo of the engine/transom ?

[rivrunner]

Hi tango....i will try to post one...thks.

[rivrunner]

tango not able to post pic. what are you looking for?....tramsom dips when I throttle up and engine dont seem to be powering up totally....engine has 20 hrs on it. Someone suggested that i don't have the right props on...but I believe these are the origional props.

[paintman]

You need to get it looked at by someone that knows what they are doing.
Did it perform properly when the seller demonstrated it to you or has it always been like this?

Sometimes things can be solved over the internet but this is one that can't.

[beamishken]

I'd doubt the engine is over propped as your probably in the lightest boat your likely to find
You don't say it seems to be reving it's nuts off and going nowhere so I'd assume not dramatically under propped either
I'd put my money on shit in the carb causing the engine to be under powered even though it's done only a few hours if it's been stored with fuel in then it's possibly blocked a jet with old fuel residue
I'd say your options are
1 strip and clean the carb ensuring the jets are all clear
2 get a tacho and see what rpm the engine is making at wot & report back
3 take the engine to an engineer and ask to investigate for lack of power

[Last Tango]

Originally Posted by rivrunner

tango not able to post pic. what are you looking for?....tramsom dips when I throttle up and engine dont seem to be powering up totally....engine has 20 hrs on it. Someone suggested that i don't have the right props on...but I believe these are the origional props.

I'm wondering where your cavitation plate is in relation to the bottom of the transom.
If the prop is too deep on a SIB it will tend to "twist" and bury the transom rather than push the boat....someone familiar with that sort of setup might recognise a pitch or diameter issue with the prop......just kicking around some thoughts.

[rivrunner]

Hi Beamis....yea i think ur right ....not over or under propped....but will check. Ur idea about the carb being blocked is intruiging.....def worth having it looked at....or are there cleaners i can put in the gas to blow any gunk that might be fouling the carb? I will bring engine to get tacho check....thks for the advice and see what they say about lack of power......thks so much 4 ur help.

[rivrunner]

Hi Tango.....interesting point....like i told bemis ...i will take it in too a tech and have it looked at......it's a short shaft so it looks fine in relation to the transom but will the rellation to the transom bottom....thks for ur advice.

[beamishken]

Originally Posted by rivrunner

Hi Beamis....yea i think ur right ....not over or under propped....but will check. Ur idea about the carb being blocked is intruiging.....def worth having it looked at....or are there cleaners i can put in the gas to blow any gunk that might be fouling the carb? I will bring engine to get tacho check....thks for the advice and see what they say about lack of power......thks so much 4 ur help.

The only realistic way to clean a carb is to strip it and remove the jets and blow through with compressed air & or carb cleaner
The tacho needs to be on whilst the engine is under load to see how the engine is reving in use.
This will tell you if it's bogged out & possibly over propped or has a running fault or if it's severely under propped and reving it's nuts off.
Look up tiny tach or you could try an optical workshop tach but that would mean running with the hood off