2510 Re-Power - Twin Yamaha 150 Four Strokes

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Well-known member
Mar 4, 2006
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new london, ct/mass
Well, I finally did it.

I decided to re-power the boat (as opposed to selling it and trading up) and the project is almost complete. The new engines are on the boat and just a few small projects remain (see below). I'll probaly bring it home this Friday.

The boat is a 1991 Parker 2510 with twin yamaha 150 2-strokes.

First of all, I went through all the obsessions over which engines (hdpi-vs-di, 2 vs 4 stroke, e-tec vs yammies vs suzukis/johnson, etc) to get.

I about pulled my hair out and finally settled on new Yamaha 4-stroke 150's. I bought in time to get the yamaha extended service incentive they offered this spring. With this project, the only original components left on the boat are the hull and fuel tank.

The new engines will get me at least another 150 miles of range, will probably almost double my fuel economy, and will be much more reliable. They will take me places, lots of places.

Anyway, If I can figure out the pic adding thing, they will appear below. If I can edit them into a sequence, I'll do that also.

[update], ok, I can't figure it out. The pictures seem to have gone in backwards. the last one is the original power, the first is the new console controls/guages, and the empty box is where the oil tanks used to be.

You can see more pics in a more cohesive order here: http://www.ctfisherman.com/cgi-bin/ulti ... 02764.html?


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Congrats! My older brother is wrestling with the same decision and is also condidering adding Yummie 4-strokes, as he too is setup with Yummie controls on his 23' Grady deep-V W/A.

In his case, the motors are late 80s Yam 150 XPs (plus rated horsepower), that have been flawless, less the use of plain 'ol carbon steel for the shift rods. (Those were a NIGHTMARE :evil: to remove, as the powerhead bolts were seized [again carbon bolts :twisted: ]). At least Yumsters finally have stainless steel hardware in critical/serviceable locations now.
I had a 2005 Yamaha F150 4 stroke on my 2004 19' Whaler Nantucket. It was rumoured to be in the mid 160's hp range, and not the stated 150hp. I usually dont put much credence into rumours of any sort, but my power curve graph and WOT speed was consistent with the higher horsepower. My numbers were much better than other Whaler Nantuckets powered with 150 Optis, 150 Verados, and 150 Hondas, where that data came from owners as well as the Whaler.com website.

I mention this because many people who would think twin 150's would be less than ideal power might be pleasantly surprised, especially considering the weight savings over the larger twin setups.
Congrats Gerg !

Did you consider going with a big single to improve fuel economy and lower maint costs ?

I ask because I have twin 200's (2-stroke) and have thought when I have to re-power a big single (300 4-stroke hopefully is available) would be the way to go. However, I understand that I would need new controls and a new bracket that would eat into the engine savings.

Anyway, enjoy !!!

Congratulations Gerg! Those Yammie 150's have certainly captured a loyal following. :wink:

The great output combined with the low weight make for an outstanding power package, especially with twins. Probably one of the best twin-motor power packages available for a 25 MV. 8)

Rich, Since you already have a bracket for twins, you might want to look at the 150's as well. Take a look at the weight of the 200 4-strokes and compare to the 150's. Keep in mind what has also been reported about the power output of the 150's being higher than labled. Going to 200's might not be worth the extra money. It's something to consider...

In my case, I have a single 225 OX66 on a bracket, so when the day comes for me to repower (hopefully, way in the future), a 300 4-stroke is the way I intend to go.

Megabyte":1t59pbnw said:
.. great output combined with the low weight ...[/img]
Great output? sure :D ! Low weight? Now I wouldn't call 466 pounds "low weight" for a 150hp motor in a 20" shaft. Now, the svelte 6-cyinder Evinrude E-Tec at 416 pounds ... now that a smoking light-weight powerplant.

Then again, when I made turboshaft engines for the Apache attack helicopter, "boomers" weighed 560 pounds and put out > 2000 shaft horsepower :shock: !

What you smokin' Kev... ;) Kidding ... don't want to turn this in an OB brand bashing thread ... but those weights quoted above are real.
True. 'Light weight' is a relative term... but it might have been considered 'bashing' to say "lighter than one of those fat-azz Hondas". :D
Did you consider going with a big single to improve fuel economy and lower maint costs ?

Nope, a lot of the fishing I do is offshore and I like the reliability of twins. A single would certainly get better economy, but for outboards I prefer twin engines.

The weight was a little bit of a concern, but when I subtracted the oil tanks and rigging that came off, it isn't a large difference over what I was running with.

I was tempted by the e-tecs, but in the end, I didn't want to be buying into the hype and dealing with potential design issues down the road. They are V1 engines, despite what the promoters say, and will surely have issues nobody knows about yet. The yammies have been shipping for years and the design is well vetted. Plus, the yammies ended up being much cheaper for the total job (partly due to re-use of stuff, partly cost avoidance).

Oh, and the dealer fixed all the disconnected wiring issues. I didn't think it would be a big deal, it just amazes me they do it.
Great specs though, I'm sure they will be very popular.
Good choice of power plants. I am a huge fan of dfi 2 strokes due to their power to weight ratio, economy, and lack of maintenance. However, with the new fuels coming out and potential water issues, I am starting to think that the standard EFI 4 strokes will have the longevity. I fear the ethanol/water causing problems with the special injectors. Time will tell! Good luck with the new power!

I've heard that 4 stroke engines have trouble with popping out of the hole...

have you noticed any difference?

I picked the boat up today. I LOVE these engines!!!

Shot out of the hole wasn't a problem - I ended up catching several items that came flying back off the dash as I pushed the throttles up. I couldn't really abuse it since I'm still in the breakin period, but I was able to open it up for short bursts after 2 hours clicked by.

Top end was in the low 40's, and it looks like the mpg will be in the 2.0 range, but it's still too soon to tell. That was with two adults and a full tank of fuel.

And after paying for the fillup below, the added economy will be very welcome.


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How does that 2510 MV sit in the water with those two F150s? I have twin F-115s, and the scuppers are only 1" above water on a calm day with a full load of fuel and two good sized adults with fishing gear.

I believe the 150s are another 40 lbs apiece, and was wondering if the scuppers would end up at or below waterline?
Yeah, the scuppers are just a hair over the waterline with a full tank and gear. It was that way with the two strokes also though.

The scuppers are another project I keep meaning to get around to. I don't like how small they are. If I took any serious green over the side, it would take forever to drain. I'm thinking of something three or four inches wide and one or two high.

Maybe I'll try to take care of both problems at once. Anyone replace their scuppers?
What kind of scupper doors do you have? And do they flop open and let water in?

Mine are about 2" tall and 5" wide and flip up/down to cover two 1" drain holes. When backing down, the doors have a tendancy to flip up and the rear portion of the cockpit floor can get 1/2" of water on it. It drains out when at rest or moving forward. They also sometimes flip up when launching from the trailer, letting a couple of gallons run into the bilge.

What I have is not the best design, and clearly not sufficient to drain a large amount of water.
Mine are simply 1"-1.5" round scuppers with a flap. The flap doesn't open and let water in, but it isn't watertight either, so if the scupper goes under water then the deck well will get wet.

These are really rediculously undersized, but it's a project that requires it to be on land.
Reel nice set-up. IMO, the 150-4s/twins make one of the very nicest rigs made (Yamaha, of course, :wink: ).

btw...new power and you have enough left over for a $456.00 fill-up!
The motors are broken in. They have about 25 hours on them, and with 3 big guys plus gear we saw a top end of 40 mph. The fuel burn at wot is around 1.6 mpg (5400 rpm), at about 25 mph, we are getting 2.0.

I still have to make some runs and actually write down all the numbers, plot them out, and see where the sweet spot is, but I suspect it's between 25 and 30 mph (4200-4600).

So far, they have been great. They stalled out a couple of times going from idle to full throttle, but I'm guessing that's nothing to worry about just yet.

Now if the seas would flatten a little, I might get a long run out to the canyons in before the kids are out of school.