Just curious about speeds people are getting out of these hulls. I am installing my 1985 200 merc an an 86 diplomat with a manual adjust plate. I was hoping for some insight from other diplomat or sportfire owners(as I think the hulls are the same) on were to start and what i can expect.
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1986 diplomat
- Thread starter tomwinder
- Start date
Mark
Well-known member
I see 57 MPH with a 130 V4 Yamaha. You will have no trouble beating 70 ... however I think it is going to be a handful over 60 in any chop at all. It may be a lot of weight off the stern at slow speeds too. I am going down to 4.5" setback. I don't like the bow rise I get with 6". If you just want to go fast, 200 HP should be a blast.
checkmate DOH!!
Member
saw 52 mph on gps last weekend on the lake with myself and two other people in the boat
I have just gotten back from hollidays and have been running the diplomat. I have been experimenting with engine heights and have only hit about a 60 mph gps or a little better. I guess that I am getting used to a padded hull, boat handles a 100% better than my sidewinder but the pad has a very different feel than the rounded bottom. jsut wanted to update everybody that helped me out.
I have been using my 22 bigblade chopper to about 5600 rpm and been limited by driving ability( ihave been alone in the boat and the battery is on the drivers side so boat is unbalanced without passenger) and have also run my 26 small blade chopper at about 5600 rpm. I think my problem is that the engine is to high up an I cannot get the boat to perform, but if go lower it will start to chine walk. Where is your cavatation plate in relation to the bottom of your boat. and what prop are you running.
Mark
Well-known member
The Diplomat hull starts chine walking at about 55 MPH. Solid engine mounts may be necessary for you to get that setup up to potential.
I have also found I cannot run the engine very high without prop slip regardless of the prop I run. The proper way to measure engine height is propshaft inches below the pad. Mine is 5" below the pad. (My Starliner is 2 1/2"...so there is a big difference there.) But this partly due to a small gearcase on a V4 and smaller diameter props. I would suspect you will be able to run higher since you are using a V6 and larger diameter props.
I doubt the choppers are the right choice for that setup. My best guess would be you would solve a lot of your problems with a 4 blade Trophy prop. Borrow a 25" Trophy and see what it will do.
My 200 EFI will push my 21' Starliner to 69 MPH on a good day with a 25" 4 blade. Your older 200 is probably closer to today's 150's...but still with that light, highly efficient hull, mid to high 60's, even 70 would be my goal.
I have also found I cannot run the engine very high without prop slip regardless of the prop I run. The proper way to measure engine height is propshaft inches below the pad. Mine is 5" below the pad. (My Starliner is 2 1/2"...so there is a big difference there.) But this partly due to a small gearcase on a V4 and smaller diameter props. I would suspect you will be able to run higher since you are using a V6 and larger diameter props.
I doubt the choppers are the right choice for that setup. My best guess would be you would solve a lot of your problems with a 4 blade Trophy prop. Borrow a 25" Trophy and see what it will do.
My 200 EFI will push my 21' Starliner to 69 MPH on a good day with a 25" 4 blade. Your older 200 is probably closer to today's 150's...but still with that light, highly efficient hull, mid to high 60's, even 70 would be my goal.
I dropped the motor way down and could hardly hang on to the wheel with the torque tab on the motor. I have a couple of buddies that own 90+ gps boats coming out to help me with setup, both tell me that the motor should be as hi as I can get it while keeping water pressure. the one guy has a 16ft carlson with 2.4 that revs 9000 and pushes at least 275 hp on that boat he get the motyor to 13/4 above the pad. To make a long storry short I am going to install a water pressure guage and start lifting until I start loosing pressure. I think I will also quit driving like a pussy and ride the chine walk a little bit.
Big Dave
Member
We had a turbo on the original 1.6l 140 but lost it in the lake when the lower unit exploded....
the new 140 looper we had a pair of rakers 13 1/2 x 20 & 22
the rakers would chine walk very bad without the jack plate but great bow lift
daren34
Member
look for a hydrolic jack plate so you can adjust it under way that way you get the best of both worlds
try a trophy and a laser II see if they are better
the choppers will only be good for top end
if you can get the motor high enough you should be able to go alot faster
i ran a 6 inch cmc with a v-4 still could have gone higher
i had to hold on tight when i jacked it up it was trying to make a left turn all the time
good luck daren
try a trophy and a laser II see if they are better
the choppers will only be good for top end
if you can get the motor high enough you should be able to go alot faster
i ran a 6 inch cmc with a v-4 still could have gone higher
i had to hold on tight when i jacked it up it was trying to make a left turn all the time
good luck daren
daren34
Member
noone else has asked but we are hoping that you have a really good dual cable steering or hydrolic
if your sterring is loose it will amplifi the chine walk
you have to stay a step ahead when flying a pad
i had finally got mine going fast enough to drive through the chine walk
(about 60) but it would roll down off and back up on the other side
felt like half of a barrell roll
i only had single cable sterring and the sterring effort was real high
i sold the boat before i did anything else to it
i don't think you need more setback but more lift
daren
if your sterring is loose it will amplifi the chine walk
you have to stay a step ahead when flying a pad
i had finally got mine going fast enough to drive through the chine walk
(about 60) but it would roll down off and back up on the other side
felt like half of a barrell roll
i only had single cable sterring and the sterring effort was real high
i sold the boat before i did anything else to it
i don't think you need more setback but more lift
daren
I did some running on the weekend and lifted to about 4 to 5" below the pad (hard to measure in the lake, above cav plate @ 3 1/2") and had the boat running 60 gps. The motor seems to be not running 100% sothe guy that I spoke about above is going to trouble shoot engine on Thursday. The guy who has raced for 35 years said I am driving it perfectly and the motor is just limiting me now. He thinks that 70MPH should be easily reached.