1980 StarCraft 181 holiday power upgrades

[Sheehandler24]

I just bought a 18.5 foot 1980 StarCraft with the 3.0 omc power plant. The boat is aluminum and weights around 960 pounds from what I understand so the little engine pushes it pretty decent (goes around 35mph full throttle and trimmed up). I’d just like to know what I could do to get a little more jam off the batt. She’s only rated for 140 horsepower so I don’t think a swap is realistic but suggestions on what would pop in easy would be nice. But if I can upgrade the engine or prop in any way that’d probably be more up my alley. It has a three blade prop, would a 4 blade make that much more difference? I’m looking to maybe pull a board when the fish aren’t biting

Thanks!

 

[jimmbo]

You actually have Power Trim? It would be a separate Switch from the Power Tilt Switch.
What is you engine's WOT Rpm range? What Rpm are you getting at WOT?

I doubt you are going to find a 4 blade Prop for that I/O. Besides 4 blades are slower than 3.

I suspect that you will get its best Performance by getting rid of unneeded Ballast(Wife, Kids, Mother in Law, especially the MIL) can be left ashore. Girlfriends and Mistresses, can remain aboard. Proper Distribution of the Load will help. A clean Hull also helps.

Your Outdrive is an Electric Shift, Make sure to use the correct Oil in it. It is speced for Type C. BRP calls it Premium Blend. There are some 3rd Party Oils that claim to be Type C, but are not Compatible with Electric Shifts.

Here is a Page from an old OMC Accessory Catalog


Don't go getting any Ideas that more Pitch will give you more speed. It will likely result in the same Speed, at a Lower Rpm, and much slower Acceleration

 

[Sheehandler24]

Yes it has power trim. The WOT is around 3500

 

[nola mike]

Yes it has power trim. The WOT is around 3500

That's way low. What prop is on there now? Have you done a compression check?

 

[airshot]

My neighbor has the 21' version of your boat with a 140 hp I/O, his boat will do 40 plus mph !! You have a problem somewhere, you should be in the 44 mph area...

 

[jimmbo]

Yes it has power trim. The WOT is around 3500

So what prop is currently on it?

 

[Sheehandler24]

17p on it now, came with a 19p aswell. The 19p needs a repair but he said it worked better. 3500 did seem low to me, felt like it should have a little more go, I was sorta wondering if maybe the last guy cranked the throttle cable down a bit may

 

[Sheehandler24]

That's way low. What prop is on there now? Have you done a compression check?

No compression check, engine seems to run and start great though

 

[Sheehandler24]

So what prop is currently on it?

17p on it now, came with a 19p aswell. The 19p needs a repair but he said it worked better. 3500 did seem low to me, felt like it should have a little more go, I was sorta wondering if maybe the last guy cranked the throttle cable down a bit may

 

[Sheehandler24]

My neighbor has the 21' version of your boat with a 140 hp I/O, his boat will do 40 plus mph !! You have a problem somewhere, you should be in the 44 mph area...

That’d be a lot more ideal haha, seems like a little engine but thes big aluminums are crazy light!