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Full Throttle
MMT 1000 Club
Joined: Sun Jan 25, 2009 8:09 pm Posts: 1268 Location: North Texas
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Got an engine problemo
Here's the deal..... Since I've put my motor back together with heads, cam, exhaust, carb, new case gasket, new lower seal, I've notice that the motor is missing when it is in it's normal trim position. If I trim it down to the point the entire prop is under water, it goes away. Trim it back up and it starts missing again. This happens in the water only. I'm running a near new stock prop and have never had this problem before. Any suggestions?
_________________ WC Custom 1854
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Fri Mar 20, 2009 5:07 pm |
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Gatorpoint
MMT 1000 Club
Joined: Tue Jan 13, 2009 8:09 pm Posts: 1175 Location: A slough behind you, TEXAS
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Re: Got an engine problemo
Do you have a rev limiter? If so, sounds like you could be bumping it. With a stock wheel, with my motor trimed out it bumps it. Had to get a prop with more pitch or lower the trim with a stock wheel deeper into the water to get it off the rev limiter.
_________________ 1854 Brotha Breaux Bateau pullin' a 35 GT arrrrahhh! Willett Welding custom boat trailer
A$$, Ca$h, or Ga$ -- NO FREE RIDES!!
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Fri Mar 20, 2009 9:03 pm |
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Full Throttle
MMT 1000 Club
Joined: Sun Jan 25, 2009 8:09 pm Posts: 1268 Location: North Texas
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Re: Got an engine problemo
Yes, it has the rev limiter. I suppose it's possible, but my tach does not suggest that I'm bumping it. With the prop all the way in the water, it's around 4100-4200 rpms. When I bump the trim up just a touch, it starts missing.
With a light load, (me and 2 boys and fishing gear) I could get 31.4 in deep water. Just me, only 28 mph????
Would it be stupid to unhook the rev limiter for a just a bit just to see if this is the problem, so long as I don't run it WOT?
_________________ WC Custom 1854
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Sat Mar 21, 2009 6:41 am |
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PaulDarensbourg
MMT Addict
Joined: Fri Jan 23, 2009 11:07 am Posts: 602 Location: Baton Rouge
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Re: Got an engine problemo
Just cut the wires and see what happens. You should be able to run that motor at atleast 4600 rpms in the water if the motor will turn up that high. What chip are you running in the limiter?
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Sat Mar 21, 2009 12:00 pm |
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J Wales
MMT Pro Member
Joined: Tue Jan 13, 2009 5:16 pm Posts: 88
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Re: Got an engine problemo
If the rev limiter is working, don't cut the wires...just pull the chip out of it. Then it will default to 5600 rpms.
_________________ 1848 Brother w/ 36 PD
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Sat Mar 21, 2009 1:54 pm |
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Full Throttle
MMT 1000 Club
Joined: Sun Jan 25, 2009 8:09 pm Posts: 1268 Location: North Texas
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Re: Got an engine problemo
the chip says 13.8
I thought it was a 4800 chip but am not sure. Anyone know?
_________________ WC Custom 1854
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Sat Mar 21, 2009 3:40 pm |
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Gatorpoint
MMT 1000 Club
Joined: Tue Jan 13, 2009 8:09 pm Posts: 1175 Location: A slough behind you, TEXAS
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Re: Got an engine problemo
_________________ 1854 Brotha Breaux Bateau pullin' a 35 GT arrrrahhh! Willett Welding custom boat trailer
A$$, Ca$h, or Ga$ -- NO FREE RIDES!!
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Sat Mar 21, 2009 8:41 pm |
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Full Throttle
MMT 1000 Club
Joined: Sun Jan 25, 2009 8:09 pm Posts: 1268 Location: North Texas
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Re: Got an engine problemo
So is my only option to switch to a bigger prop? Or do they make a 5000 rpm chip?
I tested mine out of water and it seems to kick in around 4600 rpms too.
_________________ WC Custom 1854
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Sat Mar 21, 2009 9:20 pm |
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bayouboy
MMT Elite Member
Joined: Tue Jan 13, 2009 6:08 pm Posts: 5376 Location: Venice, La
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Re: Got an engine problemo
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Sun Mar 22, 2009 2:28 am |
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deadbird8
MMT 1000 Club
Joined: Wed Feb 04, 2009 7:50 pm Posts: 3833 Location: Old East Dallas, Texas
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Re: Got an engine problemo
Not sure you want a rev limiter chip that high, I was told the stock connecting rods are the next point of failure after the valves are shimmed and ~4600 is where you want to max out. Its a protection device for over revving if the motor pops out of the water.
Go run it without the chip (defaulted to 5600) and see where your motor wants to run, just be careful. If you are hitting where the rev limiter kicks in at the optimum trim, then you can add a more agressive prop to add more engine load and adjust your RPM down (but may increase performance).
_________________ Excel 1851F4 w/ MB35HD+R CDI with a little bit of this and little bit of that
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Sun Mar 22, 2009 6:32 am |
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Gatorpoint
MMT 1000 Club
Joined: Tue Jan 13, 2009 8:09 pm Posts: 1175 Location: A slough behind you, TEXAS
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Re: Got an engine problemo
_________________ 1854 Brotha Breaux Bateau pullin' a 35 GT arrrrahhh! Willett Welding custom boat trailer
A$$, Ca$h, or Ga$ -- NO FREE RIDES!!
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Sun Mar 22, 2009 7:25 am |
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J Wales
MMT Pro Member
Joined: Tue Jan 13, 2009 5:16 pm Posts: 88
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Re: Got an engine problemo
I can testify to the fact that the push rods are the weak link and they will fail above 4600 rpms...bent both push rods on one cylinder on mine a few weeks ago letting another guy drive it in shallow water trimmed up too high. He was bumping the rev limiter (4800 chip). We were on the very opposite end of the lake from the boat ramp when that cylinder dropped. Managed to get back to the ramp on the other cylinder, and luckily the only damage was 2 bent push rods and a blown head gasket (that was from running back on the 1 cylinder only). Moral of the story...I wouldn't run it above 45-4600 without adding the beefier push rods. I ordered a 4600 rpm chip to make sure it doesn't happen again.
_________________ 1848 Brother w/ 36 PD
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Sun Mar 22, 2009 8:17 am |
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Full Throttle
MMT 1000 Club
Joined: Sun Jan 25, 2009 8:09 pm Posts: 1268 Location: North Texas
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Re: Got an engine problemo
Update: Took the boat out fishin yesterday. It definately is the rev limiter kicking in. New2duckin had a 12x14 hopkins cleaver for sale in the classifieds, so I picked it up from him. From what I've read, with a stage 1 and a cam, it ought to be about perfect. Thanks for all the help.
_________________ WC Custom 1854
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Wed Mar 25, 2009 2:19 pm |
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Gatorpoint
MMT 1000 Club
Joined: Tue Jan 13, 2009 8:09 pm Posts: 1175 Location: A slough behind you, TEXAS
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Re: Got an engine problemo
_________________ 1854 Brotha Breaux Bateau pullin' a 35 GT arrrrahhh! Willett Welding custom boat trailer
A$$, Ca$h, or Ga$ -- NO FREE RIDES!!
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Wed Mar 25, 2009 8:51 pm |
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J Wales
MMT Pro Member
Joined: Tue Jan 13, 2009 5:16 pm Posts: 88
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Re: Got an engine problemo
I look forward to hearing how it runs with the hopkins...I've though about adding a little more to mine when I do the gasket. Post back up after you get the prop with the new results, please.
_________________ 1848 Brother w/ 36 PD
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Wed Mar 25, 2009 9:46 pm |
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n.o.yat
MMT Pro Member
Joined: Wed Jan 14, 2009 10:24 am Posts: 134 Location: ponchatoula la.
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Re: Got an engine problemo
where is hopkins propeler located?
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Fri Mar 27, 2009 9:49 am |
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basinlover
MMT Pro Member
Joined: Mon Mar 09, 2009 12:24 pm Posts: 279 Location: DE Jeanerette, LA.
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Re: Got an engine problemo
I think the chip for 4800 rpm is a 17.8 k resistor you can go up a little to a 20 k and it will give about 100 rpms from what I calculated. You can usually find resistor at radio shack for about $1 but you have to carefully cut open the little yellow box and soldered it to the pins, you may also solder a potentohmeter say a 30 k and dial in what you want for rpm , but it is not very water proof.
_________________ There is no replacement for displacement!!!!
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Fri Mar 27, 2009 9:59 am |
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River
MMT 1000 Club
Joined: Wed Jan 14, 2009 8:34 am Posts: 1092 Location: Unaffiliated, SETX group has caused me to renounce my Texas Citizenship
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Re: Got an engine problemo
_________________ "Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the outcome of the vote."-Benjamin Franklin
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Fri Mar 27, 2009 11:51 am |
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Sand Man
MMT F.E.
Joined: Thu Jan 15, 2009 9:57 am Posts: 994 Location: Fort Worth, TX
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Re: Got an engine problemo
_________________ "Fight 'em until hell freezes over. Then fight 'em on the ice!"
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Fri Mar 27, 2009 12:06 pm |
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basinlover
MMT Pro Member
Joined: Mon Mar 09, 2009 12:24 pm Posts: 279 Location: DE Jeanerette, LA.
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Re: Got an engine problemo
Sorry bout the spelling had three coffee's and running wide open!
_________________ There is no replacement for displacement!!!!
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Fri Mar 27, 2009 12:12 pm |
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River
MMT 1000 Club
Joined: Wed Jan 14, 2009 8:34 am Posts: 1092 Location: Unaffiliated, SETX group has caused me to renounce my Texas Citizenship
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Re: Got an engine problemo
_________________ "Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the outcome of the vote."-Benjamin Franklin
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Fri Mar 27, 2009 12:16 pm |
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phowler
MMT Pro Member
Joined: Thu Jan 15, 2009 12:20 pm Posts: 203 Location: Flyover country
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Re: Got an engine problemo
_________________ "This hunting, This is not a sport, right? It's not a plaything. It defines who we are. It's our heart and soul. It's something that trancends a lot of things in our lives."
Rob Olson Delta Waterfowl President
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Fri Mar 27, 2009 12:39 pm |
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Gatorpoint
MMT 1000 Club
Joined: Tue Jan 13, 2009 8:09 pm Posts: 1175 Location: A slough behind you, TEXAS
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Re: Got an engine problemo
_________________ 1854 Brotha Breaux Bateau pullin' a 35 GT arrrrahhh! Willett Welding custom boat trailer
A$$, Ca$h, or Ga$ -- NO FREE RIDES!!
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Fri Mar 27, 2009 1:44 pm |
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