Most important Gauge to watch

[Stachi]

Re: Most important Gauge to watch

^^^ lol...

 

[Stachi]

Re: Most important Gauge to watch

a tire tube and a spade shovel is entry level....lol

 

[seabob4]

Re: Most important Gauge to watch

a tire tube and a spade shovel is entry level....lol

Let's see...collapsable military shovel, deflate the tube...fit your boat in the wife's purse...SHE'LL GO FOR THAT!!!

 

[rbh]

Re: Most important Gauge to watch

You guy's are floggin this one EH.

 

[Motormaniac801]

Re: Most important Gauge to watch

Thanks for the help guys.

I only have 5 gauges. the one we missed was hours, but that thing has cob webs growin in it so i never expected it to work. Now mind you this is a 74 so theres no trim gauge. were going by feel. but the Tach gauge maxes out at 6k and there is no "red zone" so idk whats good or bad. it seems to run fine. but under propped??? whats that mean? too much or not enough pitch in the prop? not big enough diameter?? as for the prop slippin? how often does that happen? doesnt it have that star nut?

 

[Stachi]

Re: Most important Gauge to watch

do we have to beg for you to tell us what boat/engine set up you have ... so one of us can help you ?????? SHEEESH!!!

 

[rbh]

Re: Most important Gauge to watch

Prop has a rubber dampner that sometime spins, so all the engines power is not converted to prop spin.

 

[oldjeep]

Re: Most important Gauge to watch

do we have to beg for you to tell us what boat/engine set up you have ... so one of us can help you ?????? SHEEESH!!!

Huh? The original post contains:

74 glastron with a 4cyl 140hp i\o MERC with the R series outdrive

 

[bigskiohio]

Re: Most important Gauge to watch

6000 rpm your motor would sound like it is ready to fly apart my guess bad tach if it sounds okay.

 

[Motormaniac801]

Re: Most important Gauge to watch

Boat yr. and make was listed in the first post. its still a 74 Glastron. with 140hp i\o merc with r series out

Just pulled the prop off, all the splines are in perfect condition with a little bit of grease on them. However i failed to find any rubber dampeners. unless im lookin in the wrong area ... Prop read (J 15 x 17 P) any ideas??? Still not sure of what Under propped means? **Theres not enough pitch so its not throwin out enough power to keep RPMS down?


Is there a way to test the tach?

 

[oldjeep]

Re: Most important Gauge to watch

To test the tach, you need to get a second tach. Something like a decent inductive timing gun will have a tach readout right on it.

No idea on your prop, since you have an R series drive. I'd start with one of the prop selector on mercurys site and see if you are in the righ ballpark.

Not 100% sure that your prop has a rubber hub, but most 1 piece props will have a ring of rubber between the spined sleeve and the main part of the prop.

 

[Motormaniac801]

Re: Most important Gauge to watch

Thanks for the help Jeep. Yeh when I pulled the prop off it I didnt see anytihng that even resemble rubber nor for an area where one might go. it seemed the splines went all the way down and even if there was a rubber bumper, i wouldnt know how it would "disengage" (if you will) the prop from the shaft.

As for the tach. I think im just going to invest in a new one. I cant imagine this one is any good.

As said before, the motor purs when im at WOT and is still pretty quiet. I did notice today though, that when I was at WOT I was only doin like 20-25mph which is not typicall with 1 other person on board. this lead me to beleive the prop was slipping...

 

[oldjeep]

Re: Most important Gauge to watch

I did notice today though, that when I was at WOT I was only doin like 20-25mph which is not typicall with 1 other person on board. this lead me to beleive the prop was slipping...

What RPM were you at? If you were only doing 20-25 with the tach reading 4000 RPM + then I'd guess that the prop is slipping. Might be worth the $130 for a new prop. If it turns out it is not the prop then you have a spare which is a good idea anyway.

As for the tach, I'd test before you spend the money and time to replace it. Doesn't take long to do the test and you can probabally borrow/rent what you need from an auto parts store.

 

[Motormaniac801]

Re: Most important Gauge to watch

Yeh, prol pushin 5000 RPM when i was goin 20-25. Im used to going 30ish at that RPM thou. I guess I just cant see how the prop would slip if the splines are all perfect.

I can say I launched from a shallow bay awhile back and rode the sand all the way out, i must have hit every rock out there too. But im just now 2 weeks and 4 problem free launches later havin problems.

Im gunna head to a local auto shop (know the owner) and see if they have something that might be able to check the tach. ill probably go from there.

Also checked the Merc prop selector site. it didnt have anything older than a 2000.

 

[sasto]

Re: Most important Gauge to watch

On an old work boat I ran for awhile had marks on the volt, temp, and pressure gauge at the optimal reading I was looking for. They were done in fingernail polish, red. Quick glance and back to work. Talking about backyard engineering....

 

[oldjeep]

Re: Most important Gauge to watch

Yeh, prol pushin 5000 RPM when i was goin 20-25. Im used to going 30ish at that RPM thou. I guess I just cant see how the prop would slip if the splines are all perfect.

What slips is not the spline. Think of the prop as 3 pieces all of them circle shaped on the inside

This isn't exactly what yours would have, but this is the spined hub with the rubber arround it which would be pressed into your prop.

A lot of the newer props have a squarish plastic hub that will strip if the prop smacks something hard enough.

Here are some better pictures of the style prop you likely have:
http://www.mercstuff.com/spunprop.htm

 

[Motormaniac801]

Re: Most important Gauge to watch

Thanks so much Jeep. Epiphany!!!

Yeh i pulled the prop off and i noticed the sleeve that came off basically converting it from all the splines on the drive shaft to 4 big groves that grabbed the prop. but i dont think that sleeve was rubber. I think it was metal. however on the inside of the prop was the male ends of those 4 big groves. But i think that might have been plastic, at least that whats i thought when i looked at it. It would def very easily be spinning then. Ill have to go out and check it now.

Is it possible to put it in gear and try spinning the prop to check if its loose? or is that not good?

 

[Motormaniac801]

Re: Most important Gauge to watch

Yeh, just checked. Everything was in perfect condition and that suare plastic peice looked brand new

 

[DaNinja]

Re: Most important Gauge to watch

I guess after twenty some years flying attack aircraft, I'm conditioned to scan all my gauges. Each gauge generally can alert you to an impending serious situation. A combination of gauge readings may be more telling as the reading of just one.

As for the 6000 rpm question...It sounds like a tach issue. Wouldn't that motor have fragged some time ago?

The tach on my Searay started jumping from 4000 to pegged on the backside of zero. No change in engine sound, but when a gauge jumps like that, it catches my attention.

 

[Stachi]

Re: Most important Gauge to watch

Thanks so much Jeep. Epiphany!!!

Yeh i pulled the prop off and i noticed the sleeve that came off basically converting it from all the splines on the drive shaft to 4 big groves that grabbed the prop. but i dont think that sleeve was rubber. I think it was metal. however on the inside of the prop was the male ends of those 4 big groves. But i think that might have been plastic, at least that whats i thought when i looked at it. It would def very easily be spinning then. Ill have to go out and check it now.

Is it possible to put it in gear and try spinning the prop to check if its loose? or is that not good?

reinstall the prop, draw a line across the entire hub and nut with a water proof marker , run it and see if the line is broken...thats how you test for a spun prop.