1988 Supra Sunsport concerns

[Beedubz]

New to this forum and having some issues with this sunsport I bought last fall. Bought the boat off eBay for 2500. Was told the boat was in good working order. I drove over 1400 miles one way to find out that the motor block was cracked. Couldn't test drive but was good enough deal that I took it home anyways. The 351 pcm ran great but the oil was white as can be. Replaced the pcm engine with a custom built 302 that was previously run on a boat with a leg not a vdrive like mine. After installation I haven't been happier motor was practically brand new when I bought it. Runs great pulls hard. After 10 hrs of use the transmission needed to be rebuilt as the clutch pack was wore out. Rebuilt it after getting a rebuild kit. Works great since. My concern to this point is the prop on it is definitely needing to be replaced. My question is this. Will a dinged up prop keep the motor from revving past 3000 rpm? That was all I could squeeze out of it today on the water. I GPS the speed and it was 33 mph. Does anyone know what the 351 pcm motor run wot and the speed? Also can anyone point me in the right direction for a good propeller. I wakeboard and kneeboard. Would like decent hole shot but would also like to have better than 33 mph top end.

[crystal waters]

speak to the fellows at Nettles props or Ski DIm.
Make aure you tell them of your engine swap.
How much horse power is your 302 puttng out?
by the way ---you ar running a direct drive --not a vdrive.

[ckracing]

I have an '86 Sunsport with a 'stock' 351. The prop replacement and new carb made a huge performance difference last season. I replaced prop with an Acme 541 (or maybe 543, don't have the invoice in front of me). Holeshot is unbelievable and top end improved. Just call Acme, they'll ask questions of you about your boat, average number of occupants, ballast or not and what you primarily do (wake boards, etc.).
http://www.acmemarine.com/our_props.php#ski

My top speed now is 43. Haven't watched the RPMs asi just put a new tach in.
Good luck!

[DAFF]

If you haven't re propped after the engine swap I doubt you have enough motor to run the old prop. There is a science to picking the right prop for any boat. There are so many variables that it is best left to the experts. Depending on you HP the engine is putting out it might be difficult to get the same performance as the stock 351.

[Beedubz]

The motor is a 302 that had about 100 hrs on it. It pulls hard for sure but its hp is up around 275. The 351 that was in it before only had 240 so hp wise it should b there. The prop thats on the boat is dinged up and actually has a bed in the one blade( previous owner not from me) i find it hard to believe that the motor wont rev past 3000 rpm. It is a direct drive 1:1 ratio trans and the carb thats on it is not a marine carb but its a brand new edelbrock that has the 100 hrs as the motor. The guy who had the motor said it pushed his boat almost as good as the new 5.7 chev he put in it. I am thinkin prop as it needs one anyways but would a dinged up prop cause that ina direct drive. I run 2 stroke outboards and never seen a bad prop cause that kind of loss in rpms

[inair]

What numbers are stamped on the prop?

[Beedubz]

I'm unsure it's still on the boat and I think the nuts are covering them. I haven't had a chance to remove it yet. I need the tool too

[Beedubz]

I found the numbers on the prop. They read as follows Ni-Bral 13LH132 or 13LH1X2 theres an x and 3 overlapping. Im unsure but hopefully someone here does. Thanks again i really want to make this thing hum on the water

[Beedubz]

I think I figured out my prop. After looking on the shaft hole the same thing is there 13LH1x2. But the x in this case is etched on about 4 times in one spot. I'm thinking when they badged the prop they put 13LH13 and crossed the 3 out because it was supposed to be 13LH12. That being said I understand this prop now. It's 13 inch diameter and a 12 pitch. This prop has one horrific bend in the one blade and its dinged up and has a bad vibration at all speeds but idle. So now back to my original question. Is this bent up beat up prop keeping the motor from revvin higher than 3000 rpm or is it possible that the prop is too big. It's funny this motor has more up but it won't rev higher than that no matter the prop.

[villain]

If it has a vibration above an idle get the prop fixed. It can mess up a lot of things.

[csl]

I was having the same trouble earlier this summer. I ended up getting a new 543 acme prop, but it didn't help all my problems. Ended up being my distributor. Timing was set right, but didn't advance right when given throttle. Put a new distributor in and couldn't believe the difference. Went from 30 mph and 3,300 rpm to 4,400 rpm and 45mph. I was really glad I got the new prop though. Made our wake much bigger and steeper for boarding. Good luck

[Beedubz]

That was my other thing. I swapped over the wiring from the 351 to the 302 not thinking anything of it. I wonder if i should swap the distributor from the 351 as well. It was the only thing i didnt swap over.