Need help deciding on a new 90hp 4stroke

[southkogs]

I just took a look at the specs on that boat. According to Tracker it's max recommended HP is 90. As a rule, on the forums we tend to suggest that you not run with a motor smaller than 75% of max HP. That would be a 67(ish)HP ... so, from my point of view you're probably under powered. Not severely, but still it's likely that the handling and performance feels slushy. Though I would think it would at least plane.

Crazy part is according to Tracker's site, they'll sell you that same boat with a 25HP!

Being, or not being, a good motor aside - I can see how you'd want some more juice behind that boat. I've not looked at new motors ... well, ever ... but if I were right now my two first stops would be Yamaha and Mercury.

 

[Faztbullet]

Transom HP rating has nothing to do with passengers...

 

[Nickm86]

I put a new Honda 60 on my 16' runabout and it planes easy and does 30+ with me, the lady and 2 girls 8 and 10.. I'm no expert but it seems like you'd want to decrease prop pitch until you have good acceleration and planning, then if you couldn't get the top speed you want only then would it be a HP issue

 

[Sea Rider]

OP has stated he hates the motor Sea Rider.Once people get that in their head its very hard to get it out.Pass the 60 on to a new happy owner and upgun .Till he does that he will pick apart the 60 big time and never be happy.

I've seen such cases before, boater hatting its current engine. But making his engine to run top than before and perfectly propped for his family, leisure current load dissipated his hate real fast. Personally like going for second boating chances before finally throwing the towel...

Happy Boating

 

[Sea Rider]

Transom HP rating has nothing to do with passengers...

Really, if so, then why is it that all boat manufacturers place a transom plate stating Max HP and Max passengers. We're dealing with HP and weight not air, right ? A must have to consider if dealing with under powered engines for any current application.

Happy Boating

 

[Revo1976]

Sorry about the late response, with all the storms lately work has had me very busy!
I first want to apologize for, if I offended anyone with my earlier posts, it wasn’t my intention I am just seriously frustrated with my boat, and my local “dealership” where I bought the boat, don’t seem to have much “service” to be had to get the issue resolved.

So I would like to start over, I bought the boat new in 2016 and at first it would “wheelie” like crazy and it would take a while before I could get the nose down and on plane. once on plane, it would hit top speed @28 mph at @5200-5500rpm but the rpms would continue to climb to @6300+rpms. I added a foil to the motor and that seemed to help some. I also upgraded my bow mount and added a second trolling battery and onboard charger.
Before placing batteries and charger permanently, I test run the boat with a buddy and my oldest boy, doing hole shots, time to plane, top speed, etc.. to determine best location for them, then I mounted them. It seemed to work ok for awhile, aside from just feeling underpowered, but lately it just won’t get out of its own way! This past Sunday, my 7 year old son and I went fishing, and it struggled to get up on plane.
IMO, as a longtime shade tree mechanic, besides the prop possibly being the wrong pitch, I really don’t think the motor is putting out what it should but I don’t know where to take it, or even where to start diagnosing it or testing it myself.

 

[briangcc]

Start with the basics. With the boat out of the water, take a paint pen and draw a line across the prop including the hub. Let the paint dry and then take the boat for a spin. Pull the boat back out of the water and compare. IF the line moved any, you've spun the prop. Prop shop or iboats can get you a new one to get the performance back.

Any damage to the prop since it was working fine and isn't now?


Also, you state your a shadetree mechanic so what do the plugs tell you? Pull them and check to see that you're operating on all cylinders.

Being a Merc outboard you should be able to find several marinas willing to work on it for you if your selling marina is a....well leaves a lot to be desired. How's that for being PC??

Reason I'm asking these questions, and those more knowledgeable will ask more, is that replacing the outboard is expensive. Have you actually priced one? I haven't so my data is dated BUT back in 2000 when I replaced my year old 120HP Force outboard which maybe had 30 hours on it with a brand new 115HP Honda 4 Stroke my price out the door including trade in was 10k. New motors and since you're looking at switching brands you'll need controls (possibly gauges) aren't cheap. New prop to solve your issue may be $300 (or more) if you go SS - cheaper if you stay Aluminum.

 

[Revo1976]

Actually I pulled the prop off Sunday to inspect it for damage, mic’d some measurements to make sure it wasn’t bent, etc... the hub looked ok also. Although I was hearing a little squealing under acceleration, like a belt slipping on a older vehicle, the only belt I could see is on top of the engine, it didn’t seem loose and I can’t imagine that the cogged belt would slip on the toothed pulleys.

 

[Revo1976]

I haven’t pulled the plugs yet, hopefully I will have time to do so this evening.

 

[Revo1976]

So aside from any tune up issues it might have, would dropping from a 13” pitch to a 12” pitch prop be a good idea? If so, should I consider a larger diameter or smaller diameter? 3 or 4 blade, and brand?

 

[ahicks]

If your engine is still able to turn up the 6300 plus rpm at wide open throttle as you have noted, going down in pitch is going the wrong way, will cause the engine to rev even higher. You need more pitch. Try a 14 or 15" pitch prop.

With 60hp running at the speeds we're talking about here, stainless props are expensive bling. An alum. prop will perform just as well.

 

[Revo1976]

The boat hasn’t hit 6300rpm since I first got it, now since it don’t want to get up on plane it’s only getting to around 4400rpm, if I get it on plane I can get @ 5400rpm, motor trimmed way up

 

[ahicks]

If it will not get to an rpm it was once capable of, and you have not changed the prop or piled on a bunch of weight, something is wrong with the engine.

 

[briangcc]

Back a couple posts ago the OP mentioned the following addtiions/changes: Battery charger, additional battery (ies), new bow mount (trolling motor I assume). Whether that's the tipping point for needing a prop change it very well could be. More data is needed...

 

[5150abf]

Just be aware if you switch brands you need to switch controls and cable also, just repowered this year and all the cables and throttle and wire harnesses were almost a $1000 on top of the engine.

 

[Revo1976]

Well after spending some time at the local marina checking out my boat/motor, and then testing out a couple different props, it seems a 4 blade 12” pitch prop made a world of difference. I’m still not overly impressed by the power, but the boat is much more tolerable now since it has some low end punch.
Now I need to figure out where the “belt squealing” sound under acceleration is coming from. It doesn’t seem likely to me that the cogged belt and pulleys would be making that noise, any ideas?

 

[wahlejim]

Do you have a new hub on that new prop? Hub slipping can cause squealing like that.

 

[Revo1976]

Yes, brand new hub. And it was doing it before the new prop.

 

[Revo1976]

So would there be any other ideas of what this noise might be?