I have an 18' 1989 Sea Ray with a 135hp Mariner (Merc) that has not
been putting out the horsepower that it used to. It really bogs under
load (pulling a skier), where it used to do fine. Just can't get the
RPM's up, can't quite get the old top end speed, etc. I've had the
compression checked, it's OK. Plugs have been replaced, been through
dozens of tanks of fuel, drainded the carbs, had it checked by a shop
with no problems found.

My latest thinking is that may be this all started when I had the oil
pump replaced after it stuck *open* (lucky me! - too much oil). I've
read all the stuff about the pro's and cons of this oil injection
system, and would prefer not to disable it.

I am wondering how I can tell what kind of mixture I'm getting at high
RPM's or at least how do I tell if this things adjusted correctly? It
seems that the throttle linkage increases the oil delivery as the
throttle is opened. The rotating valve(?) on the oil pump is adjusted
so it's never pinned all the way open or closed. It's partly open with
no throttle, and it's more open at full throttle, but not completely
open. Any chance I'm getting too much oil at full throttle? Any ideas
how to check the adjustement?

Thanks in advance!!

Dave - Fremont CA

I am wondering how I can tell what kind of mixture I'm getting at high
RPM's or at least how do I tell if this things adjusted correctly? It
seems that the throttle linkage increases the oil delivery as the
throttle is opened. The rotating valve(?) on the oil pump is adjusted
so it's never pinned all the way open or closed. It's partly open with
no throttle, and it's more open at full throttle, but not completely
open. Any chance I'm getting too much oil at full throttle? Any ideas
how to check the adjustement?

Look for sustained oil smoke under load at full throttle. If it continues
to produce visible smoking the oil ratio is fat at about 30:1 down to even
maybe 20:1. If it were fatter than 20:1 the smoke would be really thick.
At 40:1, and up the smoke is nearly invisible, at least after giving the
engine about 1 minute to clear itself under load. This is about as close
as estimated guessing will get you. If you were losing power due to excess
oil, the smoke would be so thick you would know right away, and the plugs
would probably be fouling really quick.

A merc manual should tell you how to check the oil injection system!

"Dave" wrote in message
oups.com...
I have an 18' 1989 Sea Ray with a 135hp Mariner (Merc) that has not
been putting out the horsepower that it used to. It really bogs under
load (pulling a skier), where it used to do fine. Just can't get the
RPM's up, can't quite get the old top end speed, etc. I've had the
compression checked, it's OK. Plugs have been replaced, been through
dozens of tanks of fuel, drainded the carbs, had it checked by a shop
with no problems found.

My latest thinking is that may be this all started when I had the oil
pump replaced after it stuck *open* (lucky me! - too much oil). I've
read all the stuff about the pro's and cons of this oil injection
system, and would prefer not to disable it.

I am wondering how I can tell what kind of mixture I'm getting at high
RPM's or at least how do I tell if this things adjusted correctly? It
seems that the throttle linkage increases the oil delivery as the
throttle is opened. The rotating valve(?) on the oil pump is adjusted
so it's never pinned all the way open or closed. It's partly open with
no throttle, and it's more open at full throttle, but not completely
open. Any chance I'm getting too much oil at full throttle? Any ideas
how to check the adjustement?

Thanks in advance!!

Dave - Fremont CA

Woodchuck wrote:
A merc manual should tell you how to check the oil injection system!


Is it just the copy I have, or is the Seloc Merc manual written by a
drunk Illiterate guy?

How's that fuel filter doing???? (didnt mentioned if you checked it.)

Did you change the prop to a higher pitch??? That can cause
some undesired results.

I plan to replace the the fuel hoses from the tank to the engine,
including the ball, just in case. True desperation, grabbing for
straws ;-) A friend thought it might be the fuel filter last year,
that's when I drained the carbs and discovered there was no filter....
that I could find anyway. We added a inline canester type filter.

It's got the same prop it's always had. I've actually thought about
swapping it out for something that will give me some more hull shot,
but since the boat can barely pull me out of the water on a ski these
days, I just can't see pouring money into it. Been searching
craigslist for an upgrade.. we'll see.

On 25 May 2005 17:34:07 -0700, "Dave"
wrote:

I have an 18' 1989 Sea Ray with a 135hp Mariner (Merc)

I had a 28' Sea Ray as a young man, but mine had dual 454s.

Me and the wife
http://pg.photos.yahoo.com/ph/harkra...bum?.dir=/1323

What are your top end rpms? Are they lower than they used to be? If so -
have the prop checked to make sure it is actually the same as it used to be.

Keep in mind there are a couple of quick checks to verify fuel problems.
Running at 4000 rpms (or even wide open) engage the choke (remember the
choke is a fuel enricher - it is not a butterfly system). If the engine
bogs about 1000 rpms - everything is ok w/ the fuel system. If it picks up
speed you have a lean condition due to a carb problem. If it does nothing
you have a choke problem or a fuel starvation problem.

If the plugs look good then you don't have an ignition problem.
When you say compression is OK - what do you really mean. What are the
numbers? If all cylinders are equal but down by 20 psi then this would be
the problem.

Finally - if the rpms have dropped off and you can't find any other
problem - the boat may be heavier than it used to be from waterlog or water
trapped in the hull somewhere or all the extra stuff you have put on board
thru the years.


--
Tony
my boats and cars at http://t.thomas.home.mchsi.com

-
"Dave" wrote in message
oups.com...
I plan to replace the the fuel hoses from the tank to the engine,
including the ball, just in case. True desperation, grabbing for
straws ;-) A friend thought it might be the fuel filter last year,
that's when I drained the carbs and discovered there was no filter....
that I could find anyway. We added a inline canester type filter.

It's got the same prop it's always had. I've actually thought about
swapping it out for something that will give me some more hull shot,
but since the boat can barely pull me out of the water on a ski these
days, I just can't see pouring money into it. Been searching
craigslist for an upgrade.. we'll see.

FIXED!!!!!!
It took me nearly 2 years which I'm not kicking myself for, but happy
to have my boat back.

I replaced the primer ball and fuel hose to the engine. Also cut off
about 6 inches of old hose between the tank and the ball.

Fired it up and hit the throttle and it shot right up to 5500 RPM's,
just like in the old days. Wow.

Dave