Was given an old Searay with a Johnson 70 on it. Looking for advice

[Frickinfrack]

racerone Not doubting you but, everywhere I've googled calls for a 14X9. And that is what is on it now. I'll speak with the guys down at the marina and see if they have a couple I can try before I purchase one. Maybe why it struggles to get one plane. Thanks for the tip!

 

[racerone]

A 14X9 is nonsense !!----That would be the correct prop for a loaded barge !----You are casting doubt , I would say.----Or are you saying a 14X19 with a typo on your part ?----Your friendly shop will likely recommend a 15" pitch prop to start with.

 

[oldboat1]

If you have the 9" pitch and it's unsatisfactory (difficulty planing), bump up the pitch. It's trial and error, and you know what you have in the way of performance. Try borrowing one, as mentioned, and see what the change is. (It would be good to get the tach working.)

BTW, use the 50:1 fuel ratio as was recommended. A richer oil mix is likely to just foul plugs, and may be a source of some performance issues. Jets are fixed, but open up the h.s. jets on the bottom and clear them out.

 

[Frickinfrack]

racerone
Just for my own understanding. Is a higher pitch similar to a lower gear ratio on a car or a higher one? I spoke with the guys at the marina and they have several I can try.

Oldboat 1
I'm currently using 40:1. performance issues (with the motor bogging anyway) has been fixed by lubrication the spark advance linkage. The carbs have been thoroughly cleaned and all jets have been replaced. I found a tach on ebay and will install once it gets here.

 

[racerone]

A lower pitch prop is like using a LOWER gear in a car.----Big boat / big loads means low pitch prop.-------Small boat / small loads means high pitch prop.-----Please do post what pitch you end up with !-----And sometimes folks install a low pitch prop to get the RPM they like to see.-----When in fact they need to tune-up / repair the motor to get the correct RPM

 

[F_R]

How true. Low gear may get the old truck with a worn-out engine up the hill, but it doesn't repair the old engine. I know you don't have one, but a test prop will tell the story, If it revs up to specs with a test prop, the engine is ok and you can continue to prop it by RPM. Maybe your marina has one? They are $$$$ expensive, so you certainly won't be buying one, I don't think

 

[Frickinfrack]

Took her out today and she did well. Held pretty good at about 16-18 MPH. Would have done more but the missus, well I don't need to finish that sentence. By listening to the sound of the engine, I'd say she'll do about 30 if I could actually get her wound up. Sucked some crap up out of the bottom of the tank now pretty power jets are clogged again. Still thinking I need less pitch I have no need to go any faster than maybe 20. Would rather have a better holeshot. It took a good 5-7 seconds to get up on plane which seems a little long to me. It didn't have that angry sound that 3 cylinders have. Anyone have a conversion equation to let me know what dropping each inch of pitch will do or do I just need to wing it. Is dropping 3 inches of pitch a lot? In any event, I've decided to replace stuff and put some $$ into her. Something to be said for how they made boats in the 60's. She rides like a board. Great for puttering around rivers but rough water (lite chop) is, well rough. Any all all info is appreciated. I have another post looking to put power tilt/ trim on it. Looking for any info I can fine on that as well.

 

[racerone]

You should be running with a 15" propeller I say.

 

[Keyboardman]

Are you still running a 40:1 mix? Pretty sure it's supposed to be 50:1.