259 Convincor w/ 600hp
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Re: 259 Convincor w/ 600hp
Originally Posted by Nealzy
Hi all, newby here. I read all these posts about the big HP to go fast in a CKmate. I have a 502 in my 1990 251. It porpos' like crazy at low speeds, the faster I go the less it does it. The wife hates to go fast but ya know, she has to go. Could this be the prop or the bottom? I cant afford the big engines and drives, so I need to stick with what I got.
Thanks for the reply's. If any.
Neal
Thanks for the reply's. If any.
Neal
#42
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Re: 259 Convincor w/ 600hp
My '99 259 has the same ride characteristics at slow speed. I have the same problem when my wife comes with me. She is only comfortable going slower. Of course, then she complains about the propoising. If I run anywhere below about 40 mph, it will do it. While attempting to maximize speed, I have run several props. None of which helped the porpoising. The only thing I found was to bury those stock junk Insta-Trim tabs. 2 years ago, I switched to Dana Marine hp-1000 tabs. Now the porpoising goes away with a little down tab, about #4 on my mechanical indicator. BTW, I am running a 25" P-5X for a prop.
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Re: 259 Convincor w/ 600hp
I have the same boat and it does the same thing. There is a thread that I started about (why does a boat porpose) in the general threads. There is some good info there.
Russ
Russ
#44
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Re: 259 Convincor w/ 600hp
I run 380 tabs and that alone will stop the problem. Then again I never cruise under 55mph. Thats only 3000rpm for me. Below that I'm wasting fuel. BTW I'm running a 5 blade with a 2" shorty, but if you have stock power 5 blades are not the best for you.
Bottom line- get better tabs and a 4 blade bravo 1 prop.
Bottom line- get better tabs and a 4 blade bravo 1 prop.
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Re: 259 Convincor w/ 600hp
Dave,
That is because your wife is not a sissy like mine. Did you see that Sonic?? I didnt know you got the shorty back on.
That is because your wife is not a sissy like mine. Did you see that Sonic?? I didnt know you got the shorty back on.
#46
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Re: 259 Convincor w/ 600hp
Originally Posted by checkmate454mag
Dave,
That is because your wife is not a sissy like mine. Did you see that Sonic?? I didnt know you got the shorty back on.
That is because your wife is not a sissy like mine. Did you see that Sonic?? I didnt know you got the shorty back on.
What Sonic???
The shorty lower was back to me in 10 days, Bmax takes care of me. But it may blow again, I just raised the boost... Again. 17Ibs now! I'm not advertising the top speed any more.
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Re: 259 Convincor w/ 600hp
Originally Posted by Russ G.
I have the same boat and it does the same thing. There is a thread that I started about (why does a boat porpose) in the general threads. There is some good info there.
Russ
Russ
here's the link
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Re: 259 Convincor w/ 600hp
I thought you told me that you were running with a twin engine Sonic last weekend. Or maybe it was a Scarab?
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Re: 259 Convincor w/ 600hp
For best performance you should not keep the same prop on that you use for top speed when you put a load of people in a 25’ Checkmate….Prop it to run close to max rpms at WOT for the load you have. Actually, I get lazy and leave my speed prop on, and I can still control the porpoising down to about 3000, 3200-3400 for sure, with 4 people. Russ G is probably getting sick of my saying that, but it is controllable down under 4000 with trim and throttle work. I rarely use my tabs unless I’m running thru some nasty stuff. Under 3000 and it’s very difficult to stop or controll. Just the way the hull is, it has a fast cruising speed and is an excellent top end runner.
-Craig
-Craig