I just bought a 1971 Glastron V-170 Crestflite and it came with a 1983 75
horse Evinrude. The markings on the prop say 13-1/4X17.
The engine seems to be running fine at high and low rpm's.I cant hear any
missing. It cruises nicely at low rpm's but when I give it full throttle It
sounds like it is at full
throttle, im getting about 2500 rpms if I remember right. Also with the
cover off and manually holding the throttle at full bore I can only get
about
eight miles an hour out of it according to my hand held gps. At any rate it
goes pretty slow and Im not sure why. Is this engine too small for this
boat.
The recomendation for this boats says not to use any bigger than 125 horse
so Im thinking 75 should be sufficient.I've tried adjusting the plane in all
different positions but dosnt seem to matter much
and get no noticable increase in speed. Any suggestions would be happily
appreceiated.


Thanks.... Jim

First and foremost, 75hp is enough to push that boat a lot faster than
8mph. You should be able to ski behind it. Beyond that, any number of
things could be the problem. For one, are you sure you remember 2500
rpm instead of 4500-5500 maybe? At 2500, it shouldn't sound like full
throttle. You didn't run over a plastic bag, or snag a crab trap, or
forget to haul your anchor, or have a bilge full of water do you? Or
you could have spun your prop hub, meaning the hub has broken loose
and no matter how fast your engine turns, the hub slips inside the
prop and the prop won't spin very fast.
Anyhow, those are a few possibilities. I'm sure other folk here will
add more.
Rick

On Sun, 18 May 08, "Jim Swope jr" wrote:
I just bought a 1971 Glastron V-170 Crestflite and it came with a 1983 75
horse Evinrude. The markings on the prop say 13-1/4X17.
The engine seems to be running fine at high and low rpm's.I cant hear any
missing. It cruises nicely at low rpm's but when I give it full throttle It
sounds like it is at full
throttle, im getting about 2500 rpms if I remember right. Also with the
cover off and manually holding the throttle at full bore I can only get
about
eight miles an hour out of it according to my hand held gps. At any rate it
goes pretty slow and Im not sure why. Is this engine too small for this
boat.
The recomendation for this boats says not to use any bigger than 125 horse
so Im thinking 75 should be sufficient.I've tried adjusting the plane in all
different positions but dosnt seem to matter much
and get no noticable increase in speed. Any suggestions would be happily
appreceiated.


Thanks.... Jim

Jim Swope jr wrote:
I just bought a 1971 Glastron V-170 Crestflite and it came with a 1983 75
horse Evinrude. The markings on the prop say 13-1/4X17.
The engine seems to be running fine at high and low rpm's.I cant hear any
missing. It cruises nicely at low rpm's but when I give it full throttle It
sounds like it is at full
throttle, im getting about 2500 rpms if I remember right. Also with the
cover off and manually holding the throttle at full bore I can only get
about
eight miles an hour out of it according to my hand held gps. At any rate it
goes pretty slow and Im not sure why. Is this engine too small for this
boat.
The recomendation for this boats says not to use any bigger than 125 horse
so Im thinking 75 should be sufficient.I've tried adjusting the plane in all
different positions but dosnt seem to matter much
and get no noticable increase in speed. Any suggestions would be happily
appreceiated.


Thanks.... Jim




The engine size is fine for that boat - you might want more to pull
skiers, tubes, etc. but it should go at least 30mph with a light load.

You did unhook the trailer, right?!

It sounds like the hub is spun (Google "spun hub") but that doesn't
explain the low RPM's. Since you say it sounds like it's revving higher
you may have a bad tach, too. Before you take the propeller to a prop
shop, buy a cheap aluminum prop of the same size and pitch. You should
carry a spare anyway.

If the RPM's are correct and you are getting 2500 at WOT, you probably
need a good carb cleaning. A bad stator will also cause that problem
but the carburetor is more likely and a lot less money to repair.

One last thought would be that the boat is taking water in the bilge and
weighing you down. You did put the plug in, right?!

"Jim Swope jr" wrote in message
et...
I just bought a 1971 Glastron V-170 Crestflite and it came with a 1983 75
horse Evinrude. The markings on the prop say 13-1/4X17.
The engine seems to be running fine at high and low rpm's.I cant hear any
missing. It cruises nicely at low rpm's but when I give it full throttle
It sounds like it is at full
throttle, im getting about 2500 rpms if I remember right. Also with the
cover off and manually holding the throttle at full bore I can only get
about
eight miles an hour out of it according to my hand held gps. At any rate
it goes pretty slow and Im not sure why. Is this engine too small for this
boat.
The recomendation for this boats says not to use any bigger than 125 horse
so Im thinking 75 should be sufficient.I've tried adjusting the plane in
all different positions but dosnt seem to matter much
and get no noticable increase in speed. Any suggestions would be happily
appreceiated.


A 75 hp motor should be fine with that boat. You've got problems with it
though. Could be any number of things, some of which others have suggested.
Hope you didn't pay much. And hope you're handy.

It could be a number of things but it doesn't sound expensive, just a tune-
up and maybe some ignition parts like condensor and or plugs or coils. The
coils aren't likely because it runs smoothly and not all three are going to
go at once. Solving yourself is a hassle but doable. First thing I'd check
is that the ignition advance lever is connected and adjusted properly - it
is a little bar that advances the spark when the throttle lever moves. Try
adjusting it one way and then the other to see what happens.

Are you sure that throttle is opening all the way? Sometimes the cable gets
a kink in it that prevents full movement - actually a few other parts can
prevent cable or throttle movement - check for something blocking full
travel. Could even be in the throttle box. Disconnect the cable from the
throttle bar and see if it moves farther.

Get a can of carb cleaner and run it through the carbs with engine running
- don't over do it so engine stalls. Modern gas has so many additives that
if there is old gas in the tanks or cabs they may be gummed up and you have
to take them apart and clean the whole mess - this is a lower probabilty
thing so check ignition and try cleaner first. If it was gummed up carbs it
shouldn't start at all and/or run rough.

The 17' pitch prop is a good pulling prop so it shouldn't be causing enfine
to bog down. If the hub was spun you would get lots of rpm and no go.

On Mon, 19 May 2008 18:22:15 GMT, Reno wrote:

Modern gas has so many additives that
if there is old gas in the tanks or cabs they may be gummed up and you have
to take them apart and clean the whole mess

On the contrary: modern gas has much less of a tendency toward gum
than a straight from the cracker and stills product.

They put additives in gas to, among other things slow the formation of
gum. They test for tendency to gum with a heated copper dish. I have
only one volumn of the ASTM standards. The one I have is on fuels and
I read it a while ago, I and I don't remember what all they said about
gum.

That said gum does exist. I have seen it in a garage sale lawn mower.
I have no idea how long it sat unused with perhaps years old gas in
it.

Fuel is among the most perishable of the things Army stocks. Ammo
lasts nearly forever, and food years longer than gasoline. They sell
an additive specifically to put in the fuel in your boat when you lay
it up for the winter. Never used it, never had any trouble in fifty
years.. Gum is a possibility but modern gas is really good in that
respect.

Casady

On Sun, 18 May 2008 11:58:02 -0600, "Jim Swope jr"
wrote:

I just bought a 1971 Glastron V-170 Crestflite and it came with a 1983 75
horse Evinrude. The markings on the prop say 13-1/4X17.
The engine seems to be running fine at high and low rpm's.I cant hear any
missing. It cruises nicely at low rpm's but when I give it full throttle It
sounds like it is at full
throttle, im getting about 2500 rpms if I remember right. Also with the
cover off and manually holding the throttle at full bore I can only get
about
eight miles an hour out of it according to my hand held gps. At any rate it
goes pretty slow and Im not sure why. Is this engine too small for this
boat.
The recomendation for this boats says not to use any bigger than 125 horse
so Im thinking 75 should be sufficient.I've tried adjusting the plane in all
different positions but dosnt seem to matter much
and get no noticable increase in speed. Any suggestions would be happily
appreceiated.


Thanks.... Jim


I should think that if it was a fuel filter or pump, it would run
rough. I don't know what you have along those lines, but either could
cause loss of power.

Casdy