Needing some expert advise/help before I spend some money.

[bamalivin]

I have a new boat and I have recently taken it out on the water for the first time. It is a 1990 Tracker Guide 14V with a 1989 Evenrude 20 hp. I am not sure that the engine was on it all of the life as the previous owner calmed, but it is labeled evenrude tracker on the cowl if that means anything. The motor runs great, but it feels sluggish and at WOT I am am only turning 3800 RPM which I know is not nearly enough. The prop on it is a 10x15. I plan on doing the popular HP upgrade that is mention in so many forums with sucess. Also to note the motor is currently equipped with a hydrofoil (dauphin tail) on the lower unit. It only runs about 15 MPH at WOT. I would like advise on where to start. Do I do the HP upgrade and then address the prop pitch issue or vise versa. I appreciate the advise in advance.

 

[perchjerker]

something is not right. I would figure out why its not turning the proper rpm before trying to do any kind of upgrade

perhaps the prop is not right? Maybe its not running right at high rpm's?

I dont know that motor or what the proper setup is for that boat but I bet if you could get it turn the proper rpm it would be fine

is there a hook in the hull? Prop slipping? Just a few things that come to mind\\I had a Dolefin on a few boats and it worked fine, no problems there but you could try removing it

 

[wmk0002]

I can't speak to what that rig should run or what rpms it should turn with that prop, but I would recommend doing some diagnostics on the engine before making any kind of monetary investment on it.

I'd check the sticky here on the prop wizard selection tool to see if your current prop is in the ballpark of what it should be first. It likely is though. Then test compression, spark, and fuel delivery and move forward from there. Compression and spark can both be done in 30 minutes. Tracing fuel delivery problems can be a little tedious but at least 2 cylinder and single carbed models help simplify it a bit.

 

[bamalivin]

It runs well out really well with the exception of the low rpm issue. No misses or spudders or anything of that nature. It very well could be over proped or the hydrofoil. I will check the prop wizzard as sugested and I also belive I am going to remove the hydrofoil and test to see if that changes anything.

 

[Ebug]

Wrong pitch. As was stated above, find a prop calculator and pin point what you need.

Rob

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[billyjoebigdaddy]

A 15 pitch on a 20hp seems like a lot to me. I would back it down to a 10 or even a 9. Remember for every inch of pitch you lose about 200 rpm So if you backed it down to a 10 pitch you should gain 1000 rpms. In theory of course...

 

[richg99]

I'd do what the experts above suggest as far as the proper prop.

I doubt that the RPM issues have anything to do with the foil.

But, I'd still take the hydrofoil off. They slow boats down. If you have massive porpoising problems after removing it, move some weight around. if that doesn't work ... buy some Smart Tabs.

Just my opinion, of course.

richg99

 

[billyjoebigdaddy]

Yes rich is right. Anything extra in the water creates drag. And the more drag the more demand on the motor. Just like your lawn mower. Grass drags on your mower, the taller the grass the more drag. And your mower drops rpms and bogs. Same concept in the water.

 

[bamalivin]

Thanks guys for all the sound advise. I purchased a new 11 pitch prop and am getting much better RPM. I took it out yesterday for a fishing trip and I am running around 4800 rpm loaded heavy (3 adult men, cooler, fishing tackle, 2 AGM batteriess exc.) and I am about 5100-5200 with just me in the boat with the batteries and. I appreciate the advise and help. Now I am on to my next issue that poped up yesterday with my fuel pump. If it isn't one thing it's another lol. I guess that is the price you pay to play. Thanks again!

 

[richg99]

Glad it is working for you.

Oh, and when you own a boat, you are never bored...........You ALWAYS have something to do!!...

Ha Ha richg99

 

[fl.graderman]

Do you happen to know what rpms you should be running at wot? That will determine what pitch prop you need. Then you can adjust down from there as needed for heavier loads, etc.
A factory service manual will tell you.
Maybe this is the one you need...?
https://www.ebay.com/itm/EVINRUDE-JOHNSON-OUTBOARD-1989-9-9-THRU-35-HP-SERVICE-MANUAL-549-/262346456870?hash=item3d15113f26:g:50cAAOSwu1VW8FJB&vxp=mtr

Good luck

2015 Tracker Grizzly 1448 MVX
1996 Evinrude 25hp 3 cylinder looper

 

[bamalivin]

according to the manual I should not exceed 5500 RPM at WOT. I am close enough not that it should be right after I complete the 20/25 to 35 hp mod I plan on finishing soon. My current issue is now the faulty fuel pump and trying to find the right 35 hp carb for the upgrade. Thanks again for all the advise, you guys are a plethora of knowledge!