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View Full Version : WOT 3800 rpm @ 36 mph normal?


j.mccreight@hotmail.com
05-17-2010, 11:17 PM
Hey guys, new here and new to MasterCraft, I have a '89 Tri-star with 351 ci with 267 hours, all I'm getting at WOT is 36 mph @ 3800 rpm, I've set timing to 10 btdc changed plugs all fresh fluids, throttle is moving completly from idle to wot. Boat runs great, just dont think i am getting all out of it. It's all original from carb to prop, holley 4160, 13/13 prop any suggestions will be greatly appreciated, thanks

Kyle
05-18-2010, 03:09 AM
You should be able to turn close to 5000rpm and at least a ballpark of 45mph. I dont believe that the revlimiter kicks in until 5400 or 5600. I would check the prop for being bent and such. I would also look at the strut and the alignment through the bottom of the boat. The prop should be able to be spun with you turning it with just a finger. I would bet that your secondary in your carb is not working properly and you are starving for fuel at wot. You may even take a look at the electronic igntion and make sure that the gap is set right, but I doubt that is the issue. I had a friend with this same problem and I took the motor box and ran the boat wot and looked down into the secondary while he drove and no fuel was being squirted into the intake. It was a simple carb rebuild kit and he was good to go. I think that a 4010 carb actually came on that boat. If you have a fuel line that splits off into 2 lines one going to the front bowl and one to the back bowl then you have a 4010. If you have a single line into the carb that enters in the front bowl only then you have a 4160.

JimN
05-18-2010, 07:53 AM
Hey guys, new here and new to MasterCraft, I have a '89 Tri-star with 351 ci with 267 hours, all I'm getting at WOT is 36 mph @ 3800 rpm, I've set timing to 10 btdc changed plugs all fresh fluids, throttle is moving completly from idle to wot. Boat runs great, just dont think i am getting all out of it. It's all original from carb to prop, holley 4160, 13/13 prop any suggestions will be greatly appreciated, thanks

Points, or electronic ignition module? If you have points, make sure the gap and dwell are correct. Make sure the coil is putting out enough voltage for high spark intensity, too.

TMCNo1
05-18-2010, 08:02 AM
You should be able to turn close to 5000rpm and at least a ballpark of 45mph. I dont believe that the revlimiter kicks in until 5400 or 5600. I would check the prop for being bent and such. I would also look at the strut and the alignment through the bottom of the boat. The prop should be able to be spun with you turning it with just a finger. I would bet that your secondary in your carb is not working properly and you are starving for fuel at wot. You may even take a look at the electronic igntion and make sure that the gap is set right, but I doubt that is the issue. I had a friend with this same problem and I took the motor box and ran the boat wot and looked down into the secondary while he drove and no fuel was being squirted into the intake. It was a simple carb rebuild kit and he was good to go. I think that a 4010 carb actually came on that boat. If you have a fuel line that splits off into 2 lines one going to the front bowl and one to the back bowl then you have a 4010. If you have a single line into the carb that enters in the front bowl only then you have a 4160.


A '89 TriStar doesn't have a rev limiter other than the prop and they came with a 4160 Holley.

j.mccreight@hotmail.com
05-18-2010, 08:33 AM
Thanks for the reply's, i checked the points, and replaced the coil with a msd, the prop turns freely and the carb has a single fuel hose, Is there a way to check the vacuum secondary on carb, i suspect Kyle is right the carb needs rebuilding, never been touched in 21 years.

east tx skier
05-18-2010, 10:02 AM
Thanks for the reply's, i checked the points, and replaced the coil with a msd, the prop turns freely and the carb has a single fuel hose, Is there a way to check the vacuum secondary on carb, i suspect Kyle is right the carb needs rebuilding, never been touched in 21 years.

Max RPM should be 4,500--4,600.

pkskier
05-18-2010, 12:10 PM
I have an '87 TriStar and Eastie is right on the rpm and speed should top out somewhere around 43-45 MPH. Where in Texas are you?

j.mccreight@hotmail.com
05-18-2010, 01:54 PM
North Houston (Kingwood), summitracing has a new 4160 for marine 351 should i go this route or try a rebuild, or is there something else i should try, thanks

pkskier
05-18-2010, 02:07 PM
267 hours on that boat is not very many so the carb should not be worn out. I would try a rebuild and if it doesn't work then put a new one on. I had rebuilt mine a couple times and had no problem, but 2 years ago I rebuilt and could never get it right. Put a new carb on and everything was fine, but at that time my boat/carb had almost 1,400 hrs on them.

Thrall
05-18-2010, 03:02 PM
Assuming that 36mph is your true speed (GPS), 3800rpms is about right for 36mph on a 1:1 boat. Tells me it's making power, but sounds like the secondaries aren't opening up.

etduc
05-18-2010, 03:28 PM
Hey guys, new here and new to MasterCraft, I have a '89 Tri-star with 351 ci with 267 hours, all I'm getting at WOT is 36 mph @ 3800 rpm, I've set timing to 10 btdc changed plugs all fresh fluids, throttle is moving completly from idle to wot. Boat runs great, just dont think i am getting all out of it. It's all original from carb to prop, holley 4160, 13/13 prop any suggestions will be greatly appreciated, thanks

42-45mph @4500-5000rpm. Stock. Check your secondaries, distributor advancing properly.


I'm in Longview. Eastie is in Tyler area.

east tx skier
05-18-2010, 03:40 PM
42-45mph @4500-5000rpm. Stock. Check your secondaries, distributor advancing properly.


I'm in Longview. Eastie is in Tyler area.

And one of these days, we might actually meet. :)

How strange is it that I've met guys on this forum from England and Canada, but I haven't met you?

j.mccreight@hotmail.com
05-18-2010, 03:41 PM
I think I'll order a rebuild kit, should i replace the secondary diaphram spring to a lighter one making it open sooner, or leave as is and just replace the gaskets?

j.mccreight@hotmail.com
05-18-2010, 03:46 PM
You might have seen this boat, it's grey with metallic green flake, spent its life on Lake Lewisville near Dallas will post pics later58133

etduc
05-18-2010, 04:21 PM
I think I'll order a rebuild kit, should i replace the secondary diaphram spring to a lighter one making it open sooner, or leave as is and just replace the gaskets?

If you have to ask.... you shouldn't. 8p

etduc
05-18-2010, 04:23 PM
And one of these days, we might actually meet. :)

How strange is it that I've met guys on this forum from England and Canada, but I haven't met you?

I'll be in Broken Bow, in a couple of weeks. I got a spare room available, at the Lakeview Lodge.

east tx skier
05-18-2010, 04:33 PM
I'll be in Broken Bow, in a couple of weeks. I got a spare room available, at the Lakeview Lodge.

Spoke to Taylor earlier this year. Doesn't look like I'll be able to make it this time. Hope the tradition continues though.

etduc
05-18-2010, 04:47 PM
Spoke to Taylor earlier this year. Doesn't look like I'll be able to make it this time. Hope the tradition continues though.

Has anyone told you, you look like Willy Nelson.

east tx skier
05-18-2010, 10:52 PM
Has anyone told you, you look like Willy Nelson.

No, but I get Willie Nelson a bit. ;)

j.mccreight@hotmail.com
05-26-2010, 08:49 PM
Well got the carburator rebuilt this week, also replaced intake manifold with Weiand Stealth unit, should make plenty of power now, going to test on Friday

j.mccreight@hotmail.com
05-28-2010, 09:45 PM
Well we got the boat in the water today, got top speed of 39 mph @ 4200 rpm, Picked up 3 mph and 400 rpm's, fairly smooth water 3 adults and i was able to feel the secondaries kick in at about 3500 rpm runs great just need more speed. Any thoughts?

JimN
05-28-2010, 10:34 PM
Well we got the boat in the water today, got top speed of 39 mph @ 4200 rpm, Picked up 3 mph and 400 rpm's, fairly smooth water 3 adults and i was able to feel the secondaries kick in at about 3500 rpm runs great just need more speed. Any thoughts?

What is the base timing set to and how much does the centrifugal advance add? It should add about 30 degrees and base timing should be 6-10 degrees BTDC. That being less than optimal can cost a lot of power.

Does it have the original cam and lifters? Any work done to the heads?

j.mccreight@hotmail.com
05-30-2010, 01:31 PM
base Timing is set at 10* dont know advance, everything is original from carb to oil pan and no work done to heads, i did change to a weiand stealth intake when i rebuilt carb last week, should i upgrade to electronic ignition, ie using original with a conversion or a mallory, msd unit.

JimN
05-30-2010, 10:07 PM
base Timing is set at 10* dont know to check centrifugal advance, everything is original from carb to oil pan and no work done to heads, i did change to a weiand stealth intake when i rebuilt carb last week, should i upgrade to electronic ignition, ie using original with a conversion or a mallory, msd unit.

You check the centrifugal advance by starting at idle and gradually increasing the RPM. The timing should advance smoothly as you go to WOT (Wide Open Throttle). It's not good to rev it that high without a load, so it would be preferable to do this on the water with someone else either driving or checking the timing.

If it doesn't advance or it doesn't advance smoothly, you'll need to check the springs and weights, which are located under the base plate that has the points mounted on it.

oldairboater
05-31-2010, 10:57 AM
My secondaries start coming in at 3200 rpm and it is a noticeable kick in the butt. Your speed sounds okay compared to rpm. Speed and rpm change from water conditions and weight. Been around boats all my life. You can tune and squeeze out a little more hp but big changes cost money. Simple things like weight and minor prop imperfections can drop top speed. You might be at your limit considering hp, prop pitch, and rpm.Well we got the boat in the water today, got top speed of 39 mph @ 4200 rpm, Picked up 3 mph and 400 rpm's, fairly smooth water 3 adults and i was able to feel the secondaries kick in at about 3500 rpm runs great just need more speed. Any thoughts?

j.mccreight@hotmail.com
06-06-2010, 06:05 PM
Had the boat out on san jacinto river todaynot a slight vibration any thoughts

KHall
06-06-2010, 06:13 PM
bent prop, hopefully not bent prop shaft

j.mccreight@hotmail.com
06-06-2010, 07:26 PM
Upon further inspection the shaft is not bent, but the prop is on 2 of the blades on trailing edge has two very pronounced lips. Original prop 13/13. This is going to open a can of worms but how should I prop this boat. 1989 Tri-Star 190 w/ indmar 351 250hp 1:1 transmission changed intake to weiand stealth, we usually have 4 adults and 2 kids onboard plus gear. We wakeboard and tube but also would like some top end. Before prop incident we only managed 39 mph @4200 rpm so I am lacking a little power, i am also going to upgrade to mallory elec. ignition soon. Thanks for suggestions.

cbryan70
06-06-2010, 08:08 PM
13x11.5 CNC'd is my guess

TMCNo1
06-06-2010, 08:21 PM
Upon further inspection the shaft is not bent, but the prop is on 2 of the blades on trailing edge has two very pronounced lips. Original prop 13/13. This is going to open a can of worms but how should I prop this boat. 1989 Tri-Star 190 w/ indmar 351 250hp 1:1 transmission changed intake to weiand stealth, we usually have 4 adults and 2 kids onboard plus gear. We wakeboard and tube but also would like some top end. Before prop incident we only managed 39 mph @4200 rpm so I am lacking a little power, i am also going to upgrade to mallory elec. ignition soon. Thanks for suggestions.
Go directly to the man that knows, Eric Johnson @ http://www.ojprops.com/contact_us or contact him by pm, EJ OJPROP, http://www.mastercraft.com/teamtalk/member.php?u=1537
Be prepared to give him any info he may need like, current prop info off the hub, the current altitude you use the boat at, baseline numbers of the speeds and RPM's for the current prop, boat model and year, engine size, transmission ratio, function (skiing, barefooting, surfing, boarding, tubing, etc.), ballast use, fuel load, gear, nominal # of passengers, etc. He will need it to determine the best prop for your application.

JimN
06-06-2010, 08:58 PM
Upon further inspection the shaft is not bent, but the prop is on 2 of the blades on trailing edge has two very pronounced lips. Original prop 13/13. This is going to open a can of worms but how should I prop this boat. 1989 Tri-Star 190 w/ indmar 351 250hp 1:1 transmission changed intake to weiand stealth, we usually have 4 adults and 2 kids onboard plus gear. We wakeboard and tube but also would like some top end. Before prop incident we only managed 39 mph @4200 rpm so I am lacking a little power, i am also going to upgrade to mallory elec. ignition soon. Thanks for suggestions.

How was it with 13x13? If it was good, why change it? I wouldn't assume the original prop was right then you got it.

cbryan70
06-06-2010, 08:59 PM
Jim the 13x11.5CNC is the replacment for the 13x13 forged....with way better hole shot

j.mccreight@hotmail.com
06-06-2010, 09:16 PM
It ran good no vibration,

j.mccreight@hotmail.com
06-17-2010, 08:07 PM
I got my new propeller installed from Eric at OJ Props, went with the 4 FORCE 13x13 as Eric suggested, going to take it out on saturday, so well see what she'll do thanks Eric

j.mccreight@hotmail.com
06-19-2010, 06:09 PM
Got out on the water today with the new 4 blade prop. and the boat seems to accelerate better, does hold speed better in turns and the rpm's increased to from 4200 to 4400 although the top speed was same at 38-39mph, should there be this kind of difference on a 1:1 boat, thanks

j.mccreight@hotmail.com
07-07-2010, 04:44 PM
Finally figured what was going with my speed, speedo heads were way off, I replaced the speedo heads with GPS livorsi units and its reading 42 mph at 4400 rpm. Then verified gps with a sony portable gps and now they are right on.