trim tab question

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hammerhead
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trim tab question

Post by hammerhead » Sun Jun 17, 2018 6:06 pm

just found thei forum. lots of great info. My question is my buddy just purchased a 79 f30 and he doesn't have any experience with a big boat so he asked me to help teach him. we took it out saturday and it didn't seem like the trim tabs did anything at all. plus i couldn't get top speed much over 20 mph. is that speed normal on this size boat. we will be out again tuesday and planed on seeing if tabs work at the dock.

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prowlersfish
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Re: trim tab question

Post by prowlersfish » Sun Jun 17, 2018 10:32 pm

Should run bit faster I believe What engines and what was the rpm at WOT ? When was the bottom last cleaned or hauled ?
TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat :D
2009 TROJAN RENDEZVOUS
Port Kinsale 2010 & 2011. Solomons get together 2011.

Boppy
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Re: trim tab question

Post by Boppy » Mon Jun 18, 2018 9:35 am

If the trim tabs are anything like mine on the F26 they are hydraulic and the hoses can leak, the oil reservoirs may be empty or need replacing. You need to take up the hatch and have someone operate the tabs while checking to see what's going on with them, if anything. WOT speed should be faster than 20 but that could me bottom fouling, engine tune, etc. These old Trojans are great boats, but like all of us oldsters they do need TLC at times.

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Doc Holiday
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Re: trim tab question

Post by Doc Holiday » Mon Jun 18, 2018 1:32 pm

Make sure your Trim Tab circuit breaker is on and look at the volt gauges(s) when you move the Tab button - you should see some voltage drop. I seldom use mine and half the time forget the breaker is off!

hammerhead
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Re: trim tab question

Post by hammerhead » Mon Jun 18, 2018 6:41 pm

thanks i will check this stuff on tuesday if we go
. talking east wind and that sucks for fishing

hammerhead
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Re: trim tab question

Post by hammerhead » Tue Jun 19, 2018 9:40 pm

so we tore into it tonight. no power to trim tabs at all. all fuses were fine i guess its time to start tracing wires. the engines are 318's 225hp. port engine 18000 rpms starboard 20000 rpms. port was rebuilt last year

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prowlersfish
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Re: trim tab question

Post by prowlersfish » Wed Jun 20, 2018 6:34 am

On the rpms start with cleaning the bottom
TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat :D
2009 TROJAN RENDEZVOUS
Port Kinsale 2010 & 2011. Solomons get together 2011.

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oldboat1
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Re: trim tab question

Post by oldboat1 » Thu Jun 21, 2018 8:07 pm

Might as well top off the reservoirs for the trim tabs.
Motors should run. People -- not so much.

1980 F26, Mercruiser 305
1979 14' Starcraft, 1957 18 hp Evinrude and '57 3hp Evinrude kicker

hammerhead
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Re: trim tab question

Post by hammerhead » Sun Jun 24, 2018 8:31 pm

ended up finding a broken wire.

hammerhead
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Re: trim tab question

Post by hammerhead » Mon Jun 25, 2018 9:29 pm

whats the best way to get the rpm's to match up? will just adjusting the throttle linkage work?

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P-Dogg
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Re: trim tab question

Post by P-Dogg » Mon Jun 25, 2018 11:13 pm

hammerhead wrote:
Sun Jun 24, 2018 8:31 pm
ended up finding a broken wire.
Where?

Say so folks who actually USE the search feature can know.

And yes, all else being equal, if rpms dont match, linkage adjustment seems to be in order. I have digital tachs, which read in 10s of RPMs. As a mechanical engineer with OCD, they drive me crazy!
I needed a less expensive hobby, so I bought a boat!

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prowlersfish
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Re: trim tab question

Post by prowlersfish » Tue Jun 26, 2018 6:43 am

hammerhead wrote:
Mon Jun 25, 2018 9:29 pm
whats the best way to get the rpm's to match up? will just adjusting the throttle linkage work?

When are they not matching up ? Idle speed / WOT ? Or are levers not even ? Tachs working ok , reading ok ?

Did you ever check or clean the bottom ?


what is the top speed and rpm now ?
TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat :D
2009 TROJAN RENDEZVOUS
Port Kinsale 2010 & 2011. Solomons get together 2011.

hammerhead
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Posts: 48
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Re: trim tab question

Post by hammerhead » Tue Jun 26, 2018 3:01 pm

P-Dogg wrote:
Mon Jun 25, 2018 11:13 pm
hammerhead wrote:
Sun Jun 24, 2018 8:31 pm
ended up finding a broken wire.
Where?

Say so folks who actually USE the search feature can know.

And yes, all else being equal, if rpms dont match, linkage adjustment seems to be in order. I have digital tachs, which read in 10s of RPMs. As a mechanical engineer with OCD, they drive me crazy!
the power wire came disconnected between the battery and the fuse box

hammerhead
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Posts: 48
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Re: trim tab question

Post by hammerhead » Tue Jun 26, 2018 3:17 pm

prowlersfish wrote:
Tue Jun 26, 2018 6:43 am
hammerhead wrote:
Mon Jun 25, 2018 9:29 pm
whats the best way to get the rpm's to match up? will just adjusting the throttle linkage work?

When are they not matching up ? Idle speed / WOT ? Or are levers not even ? Tachs working ok , reading ok ?

Did you ever check or clean the bottom ?


what is the top speed and rpm now ?
the bottom was painted this spring. at idle it seems ok i notice it being different around the 8000 range. port will be 8000 sb will be around 10000. wide open port 18000 ands sb about 22000. gps speed wide open is 22 mph but it definitely pulls to the port side

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prowlersfish
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Re: trim tab question

Post by prowlersfish » Wed Jun 27, 2018 6:43 am

Still could have some growth on the running gear . Do you know what size props ? Also check the tachs . While it should run faster then 20 there is no way it should be doing 20 at only 1800 to 2000 rpm . tachs are off or someone has put way to big of props on it .


btw your putting one too many 0s on your rpm numbers :D
TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat :D
2009 TROJAN RENDEZVOUS
Port Kinsale 2010 & 2011. Solomons get together 2011.

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