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First of all, I am new to boating so I am unfortunately learning somethings with my pocket book.

I have a 1980 17' Montauk with a 1991 Johnson 88 hp spl. It has consistently put out 120-125 psi on all four cylinders.

I was in shallow soft sandy/muddy water and got stuck and tried to power out of it and It over heated on me and died. It did start later and I flushed the motor but I think damage was done.

I bought a new to me replacement 1990 Johnson Spl 88 hp that came from a fresh water fly-in lake with very minimal use. It looks as if it was never used.

So, $2,200 later I would like to ask advice as to which holes to
mount the engine at and which prop would be recommended.

I will install it next week withe the aluminum prop that it is shipping with and can run it and provide any specs that would help you to help me. I have a tach and gps but that's about all.

My Best,
Danny

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I installed the new motor in the same holes because the blind hole wouldn't match if I raised the motor another hole. I have read so many threads on here suggesting to mount two holes up etc.. That I thought it might pertain to me as well.

As I mentioned in my original post, I am new to boats and just thought what I had for a motor was par for the course for an older engine.

What a pleasant experience, it starts in neutral with no advancing the throttle and just purrs with no bumps and misses. I am so happy. Can't wait to get on the water next weekend in Corpus Christy Bay.

It came delivered with a black aluminum prop that I have not removed to see the specs. My old engine had a stainless steel prop that I will investigate the specs on (I realize I should know this) but I kinda stoked that I was at least able to swap engines myself.

Still have question though, what would be the ideal prop for my boat and motor? The current stainless steel prop has plenty of dings at the leading edges.

Please advise.

Thanks,

Danny

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jetajv, Your ideal prop will be determined by the wide open throttle speed and RPM. There are many knowledgable people on here who, once they see your post, will be very helpfull in your prop selection. Welcome to boating and to WC.

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I would put the old stainless steel prop on. You motor should be mounted 2 or 3 holes up not with blind hole. If its an old OMC sst prop or an Aluminum prop, i would mount it 2 holes up. A stilletto I would mount 3 holes up.

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The motor should not be mounted all the way down on the transom like they used to do way back in 1990. Fill the two lower holes and drill two new holes on the BIA standard layout. See this article for more information on that. You want the green holes.

http://www.whalercentral.com/articles...icle_id=82

This motor (or any other motor in the future) can then be mounted two or three holes up, where the boat will perform much better.

For a propeller, you will want a 17" OMC/BRP prop or the 13-1/4" x 15" Stiletto Advantage. These are, by far, the most common propeller used on this boat/motor combination.

If the stainless propeller you have now "...has plenty of dings at the leading edges," do not use it as is. Repair it or replace it.

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Thank you all. I will fill and re-drill holes and check the specks on my current SS prop. If it is one of the ones listed in Toms reply I will repair if not I will just replace it and keep it in the boat as a spare.

Thanks,
Danny

P.S. Love the site and am a daily reader, just don't post much.

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I removed my old prop and the only markings that I could find were "JERRY" and "17" I did a web search and found nothing related to boat motor propellors.

Tom, you mention the Johnson 17 or Stiletto 13.25x15. Is the Jonson 17 also a 13.25?

If I told you that I mainly use the boat for fishing in the bay in sometimes shallow water where getting up on plane was important but that top speed was not high on my priority would you still recommend these? And if so which one over the other as I don't have the subject matter experience to compare them.

Thanks again,

Danny

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If "JERRY" appears to have been stamped into the propeller by hand and hammer, as opposed to having been cast or computer etched into it, then I would assume it was owner's identification mark or an indication it has been worked on by "Jerry's Prop Shop" or some such scenario. I would discard it.

You can use the 14" x 15" Stiletto Star if you want maximum acceleration. It is the same price as the Advantage.

OMC/BRP has made various stainless steel propeller models in this size class over the years. SST, SST II, SSP and Viper are all evolutions of the same propeller. 13-1/4", 13-3/8" and 13-7/8" diameters are all out there.

Do not worry about the diameter, propellers are not generic pieces of hardware simply described by pitch and diameter. Every model of propeller is different and once you pick the pitch, the diameter will be what it is.

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Update:
Ran with new engine and existing prop. Took my existing prop to a very respected Gulf Coast prop company Bowman's. They said the prop was satisfactory to get on the water for test results.

I also have not yet raised the motor. I was hoping to do one adjustment at a time and report back for anyone else who might find this thread helpful.

Unfortunately, my tach gets to 5000 rpm and then gets erratic (engine continues to run fine but I don't push farther). Apparently with combo of Johnson SPL and Teleflex tach I need to install a resistor.

I don't know where to purchase the correct one or how to install so if you know a tach that would not require this please advise.

Thanks,

Danny

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One other observation:
My old engine had a Doel fin (sp?) and the new engine does not. The main difference that I noticed was a very slight (slower) getting on plane without the fin. Much more noticeable once at speed, with out doel fin the boat was much more sensitive to slight movements to the steering wheel. May sound counter intuitive but the doel fin adds a bit of resistance to the steering that I guess I got used to. Also, while drifting with a drift sock I was able to somewhat steer the boat with the engine in the water with the fin better than I was able to without it.

I am reluctant to install the existing doel fin as it requires drilling holes but I've seen one that doesn't require drilling. Anyone used those?

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Danny, I'd complete testing the setup and get the correct prop on and motor at the right height before I worried about a fin. You probably won't need one once you get everything dialed in correctly.

Sounds like your tach needs an external voltage regulator to deal with the unregulated output of that motor. I may actually have one laying around - bought for an old motor and never used it. Let me see if I can find it.

Tim

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Do not reinstall a foil of any sort. They can kill the boat's performance.

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Tom, thanks for the advise, I will pass on Doel Fin.
Tim, i found a spec that called for 2000 ohm, 1/2 watt or larger resistor which I found on Mouser.com - very inexpensive I will order one of the chasis mount type of resistors and wire it up according the Teleflex troublshooting instructions.

If that works my next steps will be:

1. Run with new motor at factory "blind holes" and report RPM at WOT and Speed (GPS).
2. Drill new "green holes" and fill "blind holes" as per diagram provided in above thread and raise motor two holes up and then report RPM at WOT and Speed (GPS).

I am anxious to see the differences in these test. I must be sure the tach is working properly first and I'll pick a calm day on the bay with little or no wind during the trials and report back.


thanks,
Danny

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Danny -- That is a good plan.

Doel Fins ( and other foils) treat the symptoms of poor boat performance instead of solving the problem. Raising the motor on the transom and installing a good propeller will solve those problems