25EH 4S EFI

[caveman]

OK
If i get a tach what should i be looking at? I am trying to finish my mod and nothing is working right,and money for tach is not in my budgget right now or is prop. just looking at what i would like to do.
thanks. mike

 

[Quackrstackr]

First thing, if you know that you are hitting the rev limiter... you need to get at least a 10 pitch prop.

It looks like even a 10 was on the low side for Specknreds.

A tach really isn't going to help you much if you are hitting the limiter currently but the Tinytachs are about $30 and can be purchased online. The tach is going to help you fine tune after you get into the proper range... but it takes $ to do that, also. It is hard to find a dealer that will let you swap props until you find the one you like. Specknreds is extremely lucky. My dealer was letting me swap with what he had in stock. I clipped a sandbar that I had no idea was there and scuffed the face on my current prop so that's now what I'm stuck with. At least until I have a few hundred dollars burning a hole in my pocket to start tweaking again.

 

[taxidermist]

im not trying to steal your thread :lol: but i have a 07 15 hp mercury and when i there is no differince in 3\4 throttle and full throttle speed wise, and when i do put it on full throttle which i dont it doesnt run smooth it sounds like something is limiting it. i didnt no they had rev limiters on them? i dont no what pitch prop i have but could a higher pitch prop solve this problem?

There is either an electronic rev limiter or the valves are floating. I have the same motor and depending on the weight in the boat I hit the same knock. If I have additional weight in the boat I dont hit it.

 

[caveman]

Quackrstackr
Just got back from lake and i am going to get a tack and new prop.... It is a pain to all ways keep looking back at the warning light to see if it is over rev. I just got to find paperwork for this motor to see what props are available 8p was the low end and if i remember correct 14p was high. I just may do like i did as a fo and shoot for the middle and adjust from there.just hate to waste cash. but then a boat is a hole you just keep putting money into.........
Thanks for your help

 

[caveman]

OK i placed my order from tiny tach last night and i hope i will have before next weekend.after i get some #'s i will need help from here.

 

[caveman]

Well it has been a week and i still didn't receive the tach,just waiting is the hard part.I would much rather walk in some place and walk out with what i want.In the mean time i have been looking on line prop selector.And with their recommend a 9.25 diameter pitch 12.5 this is basted on weight.Let me say that i am not going to get this prop. or any other one until after i know my rpms.Just want to know if that prop is in the ball park.
Thanks
mike

 

[BassNBob]

Caveman, if your going to the Dale Hollow get together I will loan you mine to use that weekend.

 

[caveman]

Caveman, if your going to the Dale Hollow get together I will loan you mine to use that weekend.

bassnbob
thanks i would like to go but i need to get my boat finished first.Hope to have tach some time this week am going to call them Monday and see what is up.i may try and go for sat. just not sure. But thank you

 

[caveman]

OK
I called to day and they said it was being made 2 weeks????? well i will see.

 

[caveman]

STILL NOT HERE.

 

[caveman]

WELL AT LAST it showed up today,it was to late when i got home to play with but after work tomorrow i will look at how it dose with ears and this weekend i hope see on water. :| :|

 

[caveman]

Well today i was able to put tack on my motor and see what rpms i am running with ears/muffs and setting in driveway at idle the tinytack said after 1 min. of running avg. was 440 rpms. is this a point to start at?Is this to low /i will post more info. when i put it on water.Now is when i need input.
THANKS MIKE
PS i have pic's of how it is hooked up and of rpms can post if need be. :?:

 

[Zum]

I didn't look back but I thought this was a prop. thread?
Just knowing what your idle is,is not going to help anyone decide on the proper prop.
Sorry,if this is more then a prop thread.
If it doesn' stall and idles in gear fine,I'd say thats good to go.
People need to know what the rpms are in WOT and don't try that with muffs or even in a barrel.

 

[caveman]

I didn't look back but I thought this was a prop. thread
Yes this is about prop but everyone on here said i needed a tack for rpm before i could get the correct prop so i got one.. and i hope that i will get some good in put from the members on here as to what i need to do.After i put it in the water with some good # s.Just wanting some help.

mike

 

[Zum]

I'm sure you will get some.

 

[Quackrstackr]

440 sounds like you are in the neighborhood at idle.

The problem you are going to have is trying to figure out what pitch to get on the first shot. If you are hitting the limiter, you know right off the bat that you need one at least 2" bigger in pitch. You'll want to try and stay as close to that 6000 number as possible without running over it and you can figure 200 rpm up or down for every inch of pitch up or down... given that you stay with the same model of prop. Increased cup, diameter or adding a blade will cut down your rpms as well.