How to get rid of porpus in '92 Top Gun?
 

I'm getting quite a bit of porpusing at most speeds.It rides good between 38-44mph trim no more than 2-3 on the indicators and 60-70mph with trim as high as about 9 where i start loosing speed.Anywhere between i can run 1 or less on trim and when full fuel i'm running the tabs.Boats a '92 Top Gun HP500, TRS, 26pitch 4 blade turning out.I also boat on the Illinois river which is usually flat as glass which im sure doesnt help.Looking for advice since i havent had the boat long and quite a bit different from my previous 29 PowerQuest.

It needs some waves so it can stretch its legs............. :)

I agree with that!

get the boat out on lake mi and the porpoise will be gone. definetly not a river boat.

TRS guns are usually balanced real well. The TRS guns I run with don't have any popoise issues and they both run 26 pitch bravo 1 props turning out.

Drives spinning out IS stern lifting, the gun has a notched transom and thats one reason why they do that from what I am told, my buddy went from a mistress to a gun and said they are totally different like that...

I also hear 42's do it too...

running tab is probably only way to help it, or keep drives in a tad during cruising, I rarely use my tabs.. but the mistress rides more level even though it too will porpoise way more then my 32 Baja did..

put blowers on it and drive through the 60-70mph hop

Just tuck it in a little bit, I've driven your boat (exact boat) many times. We did the valve job and put the GPS and headliner in it

My 94 porpus' in flat water also....tabs(280K's) between 2-3 and its gone.

Hahahaha! :evilb::evilb:

My Cafe Porpuses when it's too flat and I've got it trimmed out some. I find that if I either drop a slight bit of tab down, or just tap the drives in a fraction that it goes away. Kind of a pain in the ass, but a good excuse to never run when it's too calm!!

Straight bottom cigs do not like flat water. There's a sweet spot in most every straight bottom cig I've been in while in flat water. Each boats slightly different but its somewhere with the drives kicked out a bit and tabs down a bit right before you feel the "drag" and slowing. Sone will also drop one tab a little more than the other to get the boat to roll over slightly off the vee.

Just play with it. You'll figure it out. But get it in any type of swell or chop, not only will the porpoise go away, you'll actually see the speed climb! (Less drag the better).

Small world. Great boat with some tlc.

Thats kinda the plan down the road. Reason the TRS's won't be around long. One step at a time on a limited budget

C.G. is off or your boat was built with the drives to high. I had a 89 Cafe racer with the same problem TRS drives mounted to high.
I switched the drives to spin in. It helped a little. Not much.

Tank... the only way my cafe stayed level was trimmed in and Tabs WAY down in any kind of water.

Maybe it was the way it was put together, on a Friday probably :lolhit:

I was under the impression my drives were too low. It really runs great running hard with lots of trim.

Ya got me there. We tried everything short of changing the X dimension nothing worked so I just traded it in to a dealer, and just kept on moving.

X2. Get the boat running 4,000 rpms, drives about halfway out, a bit of tab, almost in line with the drives. If the boat starts to porpoise, throttle thru it and give a bit more tab for a few seconds then tap them back up. Your boat will likely run best in 2-4' swells/chop, flat water sucks.....boring!

I have every intention of giving the ole Powerstroke a workout next season in search of bigger water:evilb:

Another question...where should the 4 barrels be coming in? (Previous efi owner) Sounds like about 4k but that seems pretty high.

If you have any questions about the engines call Jason at Performance Marine/Saris Racing Engines, he did all of the work to them....about 5-6 years ago i think, has notes on every boat hes done. I think we put a new dash In it too?
518-644-3080
Michael McMan owned the boat at the time, he ordered the upgrades.

Hahaha! We had virtually the same boats Steve - your 93 to my 95 your TRS's 525 hawks to my 3as and 525sc's. both notched transoms... I saw some porpoise that had to be dealt with now and again. Like I said kick the drives out and start to push the drives in while you felt the drag then back out...dealt with the same thing with a straight bottom'd #6 tiger with 1000's and cafe with 500's and bravos.....every boat had a sweet spot on glass. Bottom line? They don't like glass. They like 4's to start with. Seriously...big water boats, bottom line. ;);)

Do your props spin in or out?
Brett

Rotate out.

Try spinning them in see if that will help or put spacers in.
Brett

Might try swaping side for side and see what happens. If it doesnt help i can live with it til #4s, #5s or Arnesons become a reality.

It will help.

Until then.... Less trim=less porpoise. ;)

yep

I really think mine was quicker though bro. :party-smiley-004:

Carbon fiber was the key. Thats why I bought it.

i too have a kevlar 92 tg and it is no different that yours. first motors were 600 hawks, then 535 carb motors and both had a terrible hop. the boat ran 73ish with the hawks and 69 with the 535's . drives down or tabs in, that's the only way to get rid of it unless you step up the hp. now running 1000's and konrads. the x is a little higher and now have the power to drive through the hop

My 1991 Top Gun had no problems what so ever with handling. It ran 76mph super lite carbon fiber 525 Hawks trs. Was a great boat. I sold it to pool whore on here.

The boat that I had that the issues with was an 1989 Cafe anniversary edition 420's trs. This boat was totally put together wrong. Maybe it was built on a Friday :angry-smiley-038:

Ha! You know, I was always surprised how much speed I saw out of those 525sc's. then when I sold it to Jason, come to find out the motors wern't stock, they'd been gone through by the previous owner who swapped blocks out for 502's and got rid of the 454's. so, they were a lottle warmed.

Wonder where your old gun is now??

Tank, It could have been bought for 25K with the hole in it after the scope run.
I thought a guy in your neck of the woods bought it and repaired it.

i believe your "525's" put out 560 hp and 650 ft lbs of tq. the 525's that would have come in that boat original would have most likely been built by hawk marine and they were a 454 block with a small blower (174 i think) and a single dominator carb. they made about 500 hp. the hawk 600's where also a 454 block but had a 250 b&m with twin 600 holley's and they were maybe 550 hp on a good day. if your boat ran 76 mph your boat was dialed in.

Yes it was.

Out of curiousity, does anyone know what the ideal X dimension of a notched hull should be?

ask kurt (biggus) on here. he has a lot of experience with these boats, trs, konrad and other drives on a straight top gun. he is a wealth of knowledge.