Full Throttle Operating Range

[patenglish]

When the specifications list the Full Throttle Operating Range 4500-5500, why does everyone on this forum say that you need to run 5500 WOT? If this is the range, why is not OK to run somewhere in this range?

 

[JRJ]

Re: Full Throttle Operating Range

It is OK. Set-ups vary as far as RPM's at WOT. The main thing at WOT on your rig, is not to exceed max recommended RPM's (red-line). It is also OK to just cruise at 3500-4000 well below WOT as long as your engine isn't lugging.

 

[patenglish]

Re: Full Throttle Operating Range

I took it out today and it ran 40 GPS at 5000 RPMs. It is an Evinrude 88 hp with a 13.25 x 17 prop. The engine did not sound like it was lugging, but I am not sure what lugging is. Can you explain lugging?

 

[Dhadley]

Re: Full Throttle Operating Range

40 mph with that set up is about 2% slip. Thats really not very likely. We know the gear ratio and the pitch. The speed is by gps so that is accurate.<br /><br />What kind of tach is it?

 

[patenglish]

Re: Full Throttle Operating Range

Dhadley: It is a Teleflex set on post #6. What kind of tach do you recommend and what range, 6000, 7000 or 8000?

 

[Silvertip]

Re: Full Throttle Operating Range

Don't mean to jump in a post you intended for Dhadley, butit doesn't matter how high the tach registers. Your operating range is 5000 - 5500 RPM so a 6000 RPM tach would work well. So would a 7000 or 8000. The point here is you could install a tach that reads to 20,000 RPM but the needle would only move roughly 1/3 up the scale. Sort of like installing a speedometer in your boat that registers to 80 MPH but the boat only does 40 flat out. Hows that for making a simple concept complicated????

 

[patenglish]

Re: Full Throttle Operating Range

Originally posted by Upinsmoke:<br /> Don't mean to jump in a post you intended for Dhadley, butit doesn't matter how high the tach registers. Your operating range is 5000 - 5500 RPM so a 6000 RPM tach would work well. So would a 7000 or 8000. The point here is you could install a tach that reads to 20,000 RPM but the needle would only move roughly 1/3 up the scale. Sort of like installing a speedometer in your boat that registers to 80 MPH but the boat only does 40 flat out. Hows that for making a simple concept complicated????

But wouldn't a 6000 rpm tach be easier to read than an 8000 tach? A 20,000 RPM tach would be especially hard to read accurately since the scale is larger.

 

[walleyehed]

Re: Full Throttle Operating Range

OMC/BRP tach is a good one....usually go to 7000 on the scale.<br />I've been testing several different tachs lately, and researching the manufacturers.<br />If your teleflex is 2 years or older, ditch it...<br />The new, large number gauges by Teleflex are considered very accurate...their bottom-line tachs don't seem to have any consistancy other than 3 gauges I have all show slightly different numbers on the go...<br />I'm running a new BRP Tach now, and I can't give ya the part number 'cause it's in the dash, but I can tell ya, so far it matches the electronic shop tach I have to a "T".

 

[Silvertip]

Re: Full Throttle Operating Range

Reading small changes in rpm is exactly my point. The higher the scale, small changes in rpm are less noticeable.

 

[patenglish]

Re: Full Throttle Operating Range

Originally posted by Upinsmoke:<br /> Reading small changes in rpm is exactly my point. The higher the scale, small changes in rpm are less noticeable.

But I don't want to guess as to weather I am running 5500 or 5700....

 

[patenglish]

Re: Full Throttle Operating Range

Originally posted by walleyehed:<br /> OMC/BRP tach is a good one....usually go to 7000 on the scale.<br />I've been testing several different tachs lately, and researching the manufacturers.<br />If your teleflex is 2 years or older, ditch it...<br />The new, large number gauges by Teleflex are considered very accurate...their bottom-line tachs don't seem to have any consistancy other than 3 gauges I have all show slightly different numbers on the go...<br />I'm running a new BRP Tach now, and I can't give ya the part number 'cause it's in the dash, but I can tell ya, so far it matches the electronic shop tach I have to a "T".

Thanks walleyehed. This is the information I needed.

 

[patenglish]

Re: Full Throttle Operating Range

I ordered a new OMC/BRP tach on Wednesday. Will let you know how it compares to the old one. Going on weekend fishing trip next weekend and it will get a good going over.

 

[walleyehed]

Re: Full Throttle Operating Range

Good luck!

 

[patenglish]

Re: Full Throttle Operating Range

Received new tach and directions don't match tach. OMC/BRP tach. Bombardier #775662. Faria P/N TC9091A. Cust P/N 775662. It has ports:GRN, BAT, LT., SIG, SYNC STBD, SYNC PORT. The directions indicate +12V, PUL, GND, LT. Old tach was a teleflex and had Send, IGN, GND, LT. It was set on 12. The OMC/BRP has 1,2,3,4,5,6. Each terminal on the old tach had two wires attached. Red to Ign, Blue to LT, Gray to Send, Black to GND.<br /><br />Please help....

 

[b.gagnon]

Re: Full Throttle Operating Range

I just bought a Tiny Tach and love it!

 

[walleyehed]

Re: Full Throttle Operating Range

12vlt(Bat or IGN) is red or purple lead.<br />GRN needs a black lead(Ground).<br />LT is the light, blue goes there.<br />SIG is Signal or "Sender"..Grey goes there

 

[ddbyrd3]

Re: Full Throttle Operating Range

Walleyehed, you say if your teleflex gauges are 2 years old + to ditch it, what are you finding bad with them?<br /><br />I have been having serious RPM issues (reading low) I am having it verified at a shop this week-end. <br /><br />It is a "vector" series gauge... What do any of you think???

 

[walleyehed]

Re: Full Throttle Operating Range

When we've seen tach issues, it's been with Teleflex in most cases...<br />in 2004 they sent printed material stating with a box of 6 tachs I ordered that stated the new line of tachs were accurate to within 1/2%-3/4%...<br />I haven't found that to be true.

 

[ob]

Re: Full Throttle Operating Range

mean15,You didn't mention whether you had a light load or a full capacity load on your rig when you performed your 5000 rpm test run.If a rig is propped 4500 to 5000 with just a light load , it is likely to be overpropped with 3 fisherman aboard or a day of skiing.Point being is that your engine will enjoy being in the higher rpm range when at wot than at the lower end.It'll run cooler and be quicker tp plane.Not to mention ,handle better overall with varying payloads.Consider this once you get your tach accuracy issue,if you have one, worked out.My recommendation is to prop it to turn 5500 with a light load.

 

[rodbolt]

Re: Full Throttle Operating Range

you will find that v4 jonnyrude likes to coke pistons if its overloaded, thats why I try to prop them so the engine is capeable of spinning up 5500-5800 RPM. doesnt mean ya gotta run it there just means its easier on the engine and takes a bit of the load off of it.<br /> if you normally run with 3 buddies and a 95qt cooler of beer prop it to turn 5500 with 3 buddies and a 95qt cooler of beer.<br /> about half the piston failures I see are due to the ringlands coking and once rebuilt most have to be properly propped. the looper motors dont seem to be as susceptible as the crossflows to coking/carbon in the rings.<br /> but in anycase a new tach really should be verified with a known good shop tach as I have seen many and of all makes be incorrect. some as much as 1000 RPM at the top. while I am not a teleflex fan I dont like faria much either.