165 4 cyl IO

[vanwagm]

I'm looking at a 21ft. fiberglass boat w/ a Mercruiser 165 3.0L 4 cyl IO. Does anyone have any experience w/ this motor and outdrive? I'm a little concerned that this motor is a little on the small side for a boat this size. Any comments appreciated.

[Beave]

What do you want the boat for? Fishing the big lake? In that case it's probably about perfect.

Waterskiing? Probably underpowered a little.

There are a lot of 21-22ft aluminum boats with 120 Merc I/O's. With the right prop and a trolling plate a boat like that will troll down in the 2.0's easily, and hit around 30 WOT.

Figure the added weight of a fiberglass hull and a 3.0L putting out 165 is about right. It'll get up and go just fine if you're not looing for a race boat.

[vanwagm]

Yea, good question Beave. I guess I left that little detail out....this boat will be used primarily for Great Lakes trolling, and a little bit for pleasure boating. Thanks for the feedback.

[Beave]

One more thing to think about... If you're a motor guy and know this already I apologize.

You generate low-end torque (get-up and go) based on cubic inches moreso than horsepower rating. They often make multiple horsepower rated engines from the same block. For example, my Grandfather's boat has a 120hp Merc I/O. With a different carb the same block generates 140hp. You couldn't tell the difference if you were trying to pull a skier out of the water because the low end torque for the two engines is basically identical. Where you'd see the difference is on the high side where instead of a 32mph top end with his current prop he might see 36-40mph.

Same story with my outboard. It's rated 135hp and has the same block and displacement as the 150hp version. I did some research and the ONLY difference between the two motors is the ECU. Every other part on the BOM is the same except the decal on the motor. But a new 150 is almost $2000 more than a 135.

If you want to a quick hole-shot look at something with higher displacement. I'm sure you could tube behind that boat. If it could pull a 200lb man up on skis I'm not sure. You can always take it for a test drive.

[vanwagm]

Thanks for the feedback Beave. Lots to think about. I know exactly what you are talking about w/ low end torque. My plan is to take this rig out before I buy it, just to see what it does. Everything looks great, except the 4 cyl has me a little concerned.

Thanks again.
Mark

[Jason Adam]

I have been on more than one mid to late 80's 20-21' trophy hardtops with this engine and it is underpowered to the point of almost being a saftey hazard.

A good buddy had one, and with him alone and a half tank of gas, it would do 16MPH, 2 people 14MPH and 3 or more, with only a half tank of gas 11MPH. And he had it profesionally maintained. I guess if you can assure yourself that your never going to chase fish more than 5 miles offshore, you're safe, but is that realistic? Find yourself 15 miles offshore(which I was EVERY weekend last summer), and see a black wall coming at you. Theres your saftey hazard. An hour and a half ride in is not a good sceneario.

Take the boat for a sea trail, but remember that there is no econamical way to add power to a boat. What its got is what its got. There are alot of good boats out there....

[vanwagm]

Thanks for the info Jason. Did the Trophy you are referring to have the 3.0L? That performance is very depressing.....could you imagine buying that boat new, and find out it runs @ 16 MPH!!! Ouch!

This is a tough decision because this boat is in mint condition, and comes w/ all the goodies. I definately don't want to get into something that can't get out of it's own way.

Thanks for the input. It helps a lot.

[Mad Jack]

VANWAGM
I have this Same SET UP on my Boat. 24' Crestliner Sabre Hard Top. I think it is great for Big Lake Fishin??
It is not a speed demon by any means but i can get it up to about 30 MPH on the way out!!!!
Pretty Good on Fuel to.
Getaway ( Bob K.) Has seen my boat you can ask him also if you would like.
Hope This HELPS.

[Beave]

What kind of prop pitch did that boat you rode in have Jason? 15? That sounds more like a case of the wrong prop than being underpowered.

[TONGA]

My buddy has a 199419 foot Genisis mod-v with the open bow,3ltr and an alpha,,the boat new spinning a 19p wheel put up some pretty impressive speed 47gps,,,but with 6 or 7 persons it was very slow to get on top of the water,,,
when she had 200 hrs on her she would run 44gps and was slow to get on the water with 4 people,,,but my friend is very very hard on his equipment.(he is now looking for a block or a good drop in)
I know another guy who runs a 19 foot Cobia cuddy deep-v with the same motor and outdrive I am not positive but I think he is spinning a 17p wheel and his boat has no trouble at all getting up and runs about 40,,,has more hours on her also
I know they are tough little engines,,I guess the best thing to do would be to get some of your buddies together and take her for a float,,you know with a good size crew so you can judge how she performs

[Mad Jack]

Tonga
I forgot to mention that i am running the 17P Prop also in the other post.
I tried the 19P But with 4 - 5 people in boat it did make me go faster it also seem to make the motor work a little bit more. I would stay with the 17P
This is just my opinion.

[Jason Adam]

I don't know what all props he had, but I know he had two or three extra he had tried when he sold it. I don't think it was a prop issue. We're talking about a glass boat with a hard top. Most of the boats everyone has listed here for comparison are aluminum boats, so there isnt much comparison. Like I said, go sea trial the boat and go from there. Maybe it'll do 50??

[solasylum]

I have a 1987 Thompson 20 footer that weighs in at about 3500 lbs. with the 165 Mercury 228ci (I believe) and Alpha One outdrive with a 17 pitch prop. My boat will troll down below 2 mph and will hit about 30 mph wot. It seems to get on plane real fast as well.

I have been told these are very good motors and I wouldn't question this motor if the price is right.

Scott