Quick help on prop pitch purchase

[wmbreck]

I have a 15' fiberglass old Larson (pretty heavy) that I cannot get to plane because it came with just a Johnson 28spl motor. Seems like a 1991 according to this site
http://stores.ebay.com/Outboardnuts/...ar-Lookup.html
S/N - J28ESLEIB
J - Johnson
28 - hp
ES - electric start
L= long shaft - 20"
E I = 91 ....Year built
B - Mod. variation = Belgium

I will put a hydrofoil on and retrim it some, but I was told it had a 'fishing' prop put on it. this site has four aluminum 9" props (9,10,11,12" pitches) that should fit if my above year and model is right. So which pitch would help me get this thing out of the water best? Would like some top end but can't worry much about that too much since it is plowing badly now at only 10-11mph with 2 aboard and 18 mph with one anyway. Like to see 15=16 with 2 passengers and 20-22 with one if possible until we can get a 50 or 60hp for it.

Thanks!

 

[steelespike]

Re: Quick help on prop pitch purchase

This post sure sounds familiar.
"Fishing prop"I never heard of it. imo a prop is a prop.
What size prop is on it now?Should be on the barrel or under the prop nut.
can't make a prop selection without your present prop size.
Boat is probably about 750lbs. 2 adults puts you at about 1,250 with a 100 lb motor.
gas etc.under powered but doable. The 28 is capable of about 30-33 on a light reasonably fast boat.Is the motor running on 2 cylinders?Carefully un hook one plug wire at a time carefully ground it and run the motor note the results.If one is dead
it won't run when the working plug is unhooked.Lazy mans test run a cold motor for about a minute then carefully feel the plugs dead one will be cooler.
Are the throttle plates opening all the way?
I looked up a couple of tests on new 30 hp motors pontoon total weight 1377 lbs
17 mph (pontoons are really slow and hard to push. fiberglass bay/flats 983 lbs. 30 mph.
Carolina Skiff 1170lbs 28 mph. Now your 28 is likely to be a little tired and you weight may be slightly heavier but I think you can see that a sound well tuned 28 should be capable of 20 to 25 mph. 25 hp 16ft alumacraft total weight 939 31 mph.

 

[wmbreck]

Re: Quick help on prop pitch purchase

Hi "again' Admiral.

Yes familiar ground. I've just heard some many opinions and some as different as day and night. But I thank you for hanging in with me.

I can't answer your specific questions, partly because I'm new to this and maybey stupid , but mainly because the boat is at Lake Ontario and I'm in Jersey 6 hours away. But I will try all you suggest when I get there. I'm borrowing a compression tester too. I know enough to know that, even if both cylinders are firing, if one or both have 75 psi - we are doomed to watch paint dry type speeds! End of disscussion - I promise

But I'm encouraged (providing the motor isn't a dog) that I might get near the speeds you mentioned. I don't need a jet ski. I just don't want to be sweating when driving the boat because it is doing 10 mph. I'm going there in about 9-10 days and I was only hoping to get a prop that I know is right now (based on the motor model no.) because they have them here for $75+ and pitch does seem to matter according to many. Up there everything takes days to find, order, and ship - and I'm never have that long a period there at one time to do that. But as always, this is all about $$$ and being forced to deal with whatever you can afford.

Thanks again, and I will let know what I find and if anything I try helps short of a new 50hp motor next season.
Bill

 

[steelespike]

Re: Quick help on prop pitch purchase

Good luck;a couple of points.Remove the cover and with motor off in forward operate the throttle to wide open note the linkage action as the stator under the flywheel rotates does the cam pick up the carb linkage.And in turn does the carb throttle plate open all the way? When doing your compression test note the location and condition of the plugs.Should be brownish and dry.Check the wires for wear where they might rub on the motor.Hand cranked 100 psi compression would be excellent and its important that it is even between cylinders within 10%. Sometimes a sea foam treatment will loosen rings and inprove compression.Keep us posted.
I'm in central NY only about 50 or so miles from Ontario and boated most of my life on the St Lawrence.

 

[wmbreck]

Re: Quick help on prop pitch purchase

Thanks again. I'll try what I can and what I don't grasp I'll grab the retired auto mechanic down the road. He's crude and a pain in the neck and tries to make you feel stupid if you need help - but knows a lot. Worth the pain I guess

First thing I did was put new rightly gapped plugs in her. The throttle not being all the way out intrigues me. It has felt like that since day one to me but I just attributed it all to 'no replacement for displacement'. But you, and so many others, have said I should be in the 20-25+ range may mean this is doable if the motor is not toast. I'll be there almost 2 weeks so maybe I'll even check in. We have dial up using a cell pnone as a modem 14.kbs = slower than the boat !

Bill

PS Just wondering where on the river you hung out? We are 15-20 minutes from Cape Vincent. We are on the U.S. side around Three-mile Bay if you know where that is. If we look straight out, Sacketts Harbor is about 5 miles out. If I ever get this boating right I'll may brave the voyage. We are 2 miles down the road from a little campground called "Shangri-la" just in case you might have passed it sometime. My wife's parents bought this place 45 years ago for $9K. 100' on the water and I've been going there for 30 years. Most beautiful place I know when it is right! So nice it keeps me from ever even thinking divorce Wish the bass fishing would come back. Very poor since some ship dumped those stinking invasive species 'Gobes' into the River a few years back. Back to work. Thanks!

 

[steelespike]

Re: Quick help on prop pitch purchase

When you changed the plugs do you remember their condition Shiny black,dusty black, brownish did they both look the same?As far as the throttle operation I described just continue open and close the throttle and observe the mechanism operation. If you have some time on the new plugs note their location and tell me what they look like.
The Cape is a little up river from Clayton We were on Murray Island a little down river from Clayton.Never been to the cape by boat but by car a few times. Clayton has the boat museum definately worth the ride by car or boat.Not free but excellent.Have a great time.