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200 hp johnson j200txcor 1988

L

lstring

Contributing Member
"i have a 200 johnson,compress

"i have a 200 johnson,compression 75- 80 on all cyl,it is running a 4 blade prop 14 1/4 by 19. it is on a 20ft seacraft offshore, it is having trouble reaching top speed. i noticed that cavation plate is 2" below bottom of boat. would this hurt or do i need to raise motor? or rebuild motor?"
 
"Leon, 75-80 sounds a little l

"Leon, 75-80 sounds a little low, but since it is consitent accross all cylinders, before I rebuilt it, I would have it tested with another gauge - yours may just be reading low.

The 2 inches below the bottom of the boat will cause a bit of drag, but not so much that you would notice a huge difference and since it's not likely the motor "slipped" down those 2 inches on it's own, it has obviously been like that since the motor was mounted.

When you say "having trouble reaching top speed" what exactly do you mean?

It's sluggish getting up to top speed?

You think it should get a top speed of "x" and it isn't?

It would previously run at say 40 mph now it only will do 32?

Is this whole rig new to you? or just started acting up?"
 
"it will only turn about 4000

"it will only turn about 4000 rpm. the boat is new to me.it takes a while to plane out.never reaches propper rpm.it starts right up and idles great,...too mutch prop ?"
 
"After I posted I ran some num

"After I posted I ran some numbers through my prop calculator and unless I really have something out of whack it looked like you had "not enough prop".

A 20 foot Seacraft should weigh in at about 1750 pounds (dry) add the motor, rigging etc, that would take it up to maybe 2300-2400 pounds, even with 4 adults on board with their junk for the outing, a 200 horse should push that along, at about 40 mph, turning a 15" diameter, 23 pitch at about 5200 rpms - so at the very least, I don't suspect your prop.

Is the boat, motor or both "new to you"?"
 
"i bought the boat last year o

"i bought the boat last year on e-bay ,the motor was given to me.so i put them together. trying to find out why it has no power.looks like i need to go through the carbs.agreed? also the vro has been disconnected.hoses pluged and wires unplugged.could that be part of the problem ?"
 
"No, the disconnected VRO woul

"No, the disconnected VRO would not affect the rpm's in any way.

Before I tore into the carbs though I would confirm the ignition is working fine.

Have you tested for spark at all cylinders?

The igniton on your motor is kinda split in half. One powerpack sends spark to cylinders 1, 3 and 5, the other to 2, 4 and 6. Have you confirmed that you haven't lost a whole bank?

That would certainly restrict the performance of the motor..."
 
"never checked for that ,it se

"never checked for that ,it seams to run fine but i will check and get back tomorrow. i realy thank you for your time,if there is anything you think of let me know. thanks agin...leon"
 
if he lost a whole bank......i

if he lost a whole bank......it wont turn 4000...maybe 3000 at best....ck fuel del thru out..
 
"Do not want to 'interrupt

"Do not want to 'interrupt', but:
I will suggest the following.
Lift the engine on transom to cav plate is about 1/2-1 inch above bottom, when engine is trimmed with cav-plate parallel to bottom.
23" prop as mentioned in the 40 Miles range is faaaar out, more likely a 17" would be better.
Get the basic installation right before messing with the engine providing it starts and runs without any general issue."
 
"yep,...75 -80...i would def--

"yep,...75 -80...i would def--do a de-carb...over and over....i bet it would come up...if u get up to about 90--95....that would be --ok--on that eng.."
 
i found the decarb process on

i found the decarb process on iboat web site . thanks for all your help........leon

p.s i love this website.
 
"When de-carbing, buy the orig

"When de-carbing, buy the original OMC/BRP Engine Tuner with the fitting for the valve at the primer solenoid. Makes it all a bit easier."
 
"Morten, that's 200 horses

"Morten, that's 200 horses only pushing a (barely) 20 foot boat with a dry weight of about 1750 lbs. It should be able to turn a fairly "big" prop.

I look after a couple of 18.5 footers, 1500 pounds dry, each with a single 90 horse turning a 17 pitch and they get into the mid/high 30's at WOT.

Depending on the year of his SeaCraft, it was only rated for 175 horse (however, I will assume 4 stroke). Given how this is rigged, 19 pitch sounds like the low end to me and only if he was continuously running quite heavy."
 
"Do a slip calculation. Gettin

"Do a slip calculation. Getting above 15%, You are rigged rather un-economical.
Ran my BW 17 with 150 Fichts and other 150, up to 225, hit 50Knots on GPS with 150, never went above 20" Rakers.
With a decent working 23" You will never get it out of the water. Might be able to trim it out, make a lot of spray and blow air, but that does not push forward.
20 'offshore' indicates a deep V (18-22 degree), rather heavy to push, and a hull wheight above normal Bayliner standard unless made of carbon fiber.
Let us see if he gets back."
 
"hello guy's, i did the ch

"hello guy's, i did the check on fire to all cyl, i do have fire on all.haven't had time to raise motor yet.my boat is a 1976 seacraft.i know this boat should at least hit propper rpm given the size of motor.thats why im here to try to figureout.you guy's know a lot more than i do."
 
"Yes, definately get it rigged

"Yes, definately get it rigged up correctly. If nothing else it will help with performance once all is working properly.

Personally, I would invest in a jack plate. Don't have to go super fancy (hydraulic), but a manual 4" model with maybe 6" set back would allow you to fine tune the install, and save drilling (extra) holes in the transom, which would be required if the motor was simply remounted."
 
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