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Your Average speed with an outboard 9.9?

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Guero
Deckhand

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Mexico
6 Posts

Initially Posted - 11/30/2009 : 09:43:39

Hello All,

I recently purchased a Catalina 25 1982, Standard Rig. It has an 2 strokes outboard Johnson Sail Master 9.9 (Unknown Year).

Yesterday, we were 6 in the boat and while motoring out of the port to the sea, I noticed that I was not doing more than 3 knots with throttle to almost 3/4 to the max.

3/4 will usually give me 4 to 4.5 kts on 3/4 throttle, on a flat, 0 wind sea.

Is my engine "tired" or this is the average performance I should expect from a Johnson 9.9?

Not that I am in a hurry but with waves on the gulf and upwind, 3/4 will give me around 3 knots.

Your opinion?

__
Steve "Guero" Poirier
1982 C25 SR/FK
Yucalpeten, Yucatan, Mexico

Edited by - on

Sloop Smitten
Master Marine Consultant

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USA
1181 Posts

Response Posted - 11/30/2009 : 10:12:54

Guero,
At 3/4 throttle you should be able to reach hull speed, about 6 knots or so. Have you checked the bottom of your boat for growth? When I bought mine the keel was so loaded up with barnacles and other sea critters that it would barely reach 5 knots. You may need to have it cleaned. If you still suspect the motor I would start by replacing the spark plugs. Those two cycle engines can run on just one plug but with a substantial power loss.

Edited by - on

Guero
Deckhand

Members Avatar

Mexico
6 Posts

Response Posted - 11/30/2009 : 10:27:20

Sloop Smitten,

Great advice, I will get the bottom cleaned and also change the spark plugs while I'm at it, I will post the results, thanks!

Edited by - on

Renzo
Admiral

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USA
621 Posts

Response Posted - 11/30/2009 : 10:30:26

A 9.9hp should, eventually, push the C-25 at close to hull speed (6.3kts approx) with the throttle full open on a flat calm day with 2 to 4 average weight people on board.

3kts at 3/4 throttle seems a little slow but factors that could account for it are:

The condition of your hull below the water line. (clean? algae growth? Kelp? Barnacles?)

The are your spark plugs new or old? are they clean?

The current where you were motoring?

Is your Knot meter still accurate?

Finally(and I'll put this as delicately as I can)were all of your guests of average weight?

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 11/30/2009 : 10:34:14

Steve,
On our Tohatsu 9.8 (4 stroke), we can go about 4.5 knots at 1400 rpm, and 6 knots at about 3000. Our hull tends to get fouled with grass if I don't stay on top of scrubbing it, but I've found that sailing/motoring at "high" speed tends to slough the growth off fairly quickly, it's not very firmly attached. If you have barnacles or mussels on your hull, I'd expect a large drop in speed.

I agree with the folks about changing out the spark plugs, it can't hurt and can certainly help. Fresh gas is a good idea too.

For a comparison we used to have a Johnson Sailmaster 8hp two stroke on our boat. I could pretty easily get up to over 5 knots with it. I was able to sell it immediately on Craigslist for $800, which is about half of a brand new four stroke 9.8 Tohatsu. You could probably sell your 9.9 for at least that. Mine sold the first day I put up the ad.

Edited by - on

Guero
Deckhand

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Mexico
6 Posts

Response Posted - 11/30/2009 : 10:50:53

The condition of your hull below the water line. (clean? algae growth? Kelp? Barnacles?)


I will get it cleaned today.

The are your spark plugs new or old? are they clean?

I will clean them today as well!

The current where you were motoring?

There were not much current, but I'll keep an eye on it!

Is your Knot meter still accurate?

I guess it's pretty accurate, it's from the GPS, and when I sail I'm faster than the engine at 3/4 with 10 knots of wind, 4-4.5 on a beat, around 5-5.5 on a reach, that is with a furler on the main. (don't like it, but nice lazy mechanism)

Finally(and I'll put this as delicately as I can)were all of your guests of average weight?


:-) We were 6 adults, 3 men normal weight and 3 women around 120 pounds, and yes, this came into my mind yesterday as I was motoring hehehe, I started doing some quick weight maths :)

So I will do the spark plugs and have the hull cleaned and post back my results.

delliottg, I will definatly get the hull cleaned asap and check the spark plugs!

This community is amazing, thanks Renzo, delliottg and Sloop Smitten

Edited by - Guero on 11/30/2009 10:51:57

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 11/30/2009 : 10:51:27

Run the engine a little before pulling the plugs, and see whether one plug is wet. That would indicate you're only running on the other cylinder--possibly due to the plug or spark wire. Six in he cockpit plus some thrust from the outboard may cause the boat to drag its transom--slowing it, but a 9.9 should still easily do 5+ knots except in serious chop.

Edited by - Dave Bristle on 11/30/2009 10:54:27

Dave5041
Former Mainsheet Editor

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USA
3758 Posts

Response Posted - 11/30/2009 : 11:06:11

6 hp is enough to push these boats to hull speed in modest conditions; we all get 9.9's (2 or 4 stroke, 9.9 is 9.9) because it it the financial sweet spot for XLS and electric start/alternator. My old 9.9 Johnson would cruise at 5kt @ 1/2 throttle, and the stern would squat at 3/4 throttle (hull speed limit). My Johnson sold quickly to a boater who drove over 200 miles each way to pick it up. It's a great engine if you don't mind the noise.

Edited by - on

dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 11/30/2009 : 11:17:45

Check your prop. You might have a low pitch/high thrust prop that may be limiting your high end speed. Kind of like running in first gear.

Edited by - on

Even Chance
Captain

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USA
393 Posts

Response Posted - 11/30/2009 : 11:24:36

If you're using your GPS to measure speed, remember to account for tide or current. I was really excited when I hit 7.6 knots on a beam reach, and frustrated when I could only make 3.5 knots under power, until I realized I was dealing with 2 knots of current -- the first time pushing me and the second time slowing me.

Edited by - Even Chance on 11/30/2009 11:25:30

PCP777
Master Marine Consultant

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USA
1225 Posts

Response Posted - 12/01/2009 : 14:06:32

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Guero
 Hello All,

I recently purchased a Catalina 25 1982, Standard Rig. It has an 2 strokes outboard Johnson Sail Master 9.9 (Unknown Year).

Yesterday, we were 6 in the boat and while motoring out of the port to the sea, I noticed that I was not doing more than 3 knots with throttle to almost 3/4 to the max.

3/4 will usually give me 4 to 4.5 kts on 3/4 throttle, on a flat, 0 wind sea.

Is my engine "tired" or this is the average performance I should expect from a Johnson 9.9?

Not that I am in a hurry but with waves on the gulf and upwind, 3/4 will give me around 3 knots.

Your opinion?
<hr height="1" noshade id="quote"></blockquote id="quote">

My bottom is dirty, and that's about what I get from a 2007 Mercury 9.9 long shaft.

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 12/01/2009 : 15:13:00

<blockquote id="quote">quote:<hr height="1" noshade id="quote">My bottom is dirty, <hr height="1" noshade id="quote"></blockquote id="quote">

So many places to go with that, but I'm restraining myself...

Edited by - on

PCP777
Master Marine Consultant

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USA
1225 Posts

Response Posted - 12/02/2009 : 08:22:23

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by delliottg
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">My bottom is dirty, <hr height="1" noshade id="quote"></blockquote id="quote">

So many places to go with that, but I'm restraining myself...
<hr height="1" noshade id="quote"></blockquote id="quote">

Edited by - on

Steve Milby
Past Commodore

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USA
5895 Posts

Response Posted - 12/02/2009 : 09:42:20

Based on the speeds that you say your boat can reach under sail, I doubt that the bottom is especially foul. If the bottom was so foul that it could only do 3 knots under power, it wouldn't be able to sail 4-5 knots under sail, and it's tacking and maneuvering would be horrible.

The only two causes that I know of for a sailboat to be that slow under power are: (1) you were running against a strong tidal current. (Once, I had 7 knots showing on the knotmeter of a boat I was chartering, but it was going against a 7 knot current, and the boat came to a stop.) (2) The other possible cause is that you were motoring into the wind, with big waves striking the bow of the boat. When that happens, each wave slows the boat so much that sometimes it can barely make any headway.

Edited by - on

PCP777
Master Marine Consultant

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USA
1225 Posts

Response Posted - 12/02/2009 : 13:27:18

Might be a silly question but are you disengaging the choke after it's warmed up?

Edited by - on

Jmurfy
Navigator

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USA
176 Posts

Response Posted - 12/07/2009 : 22:38:42

My 9.9 yamaha will push me along at 5.1 knots at 3/4 throttle with 2 to 3 foot waves and some headwind on Lake Michigan.

Edited by - on

KenDavis
1st Mate

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USA
69 Posts

Response Posted - 12/08/2009 : 08:51:17

This forum will help with any problem you can encounter with a C25.

But please, PLEASE! post us some photos of a Catalina 25 sailing the Yucatan.

It will do us all some good.

Edited by - on

Guero
Deckhand

Members Avatar

Mexico
6 Posts

Response Posted - 12/11/2009 : 06:59:35

Good news! Replacing the spark plugs gave back the "punch" to the engine, could reach hull speed.

Now new problem: When running it at 3/4 or more, after some time it will start reving up like if it was in neutral than go down until it stall or you throttle down back to about 1/2. Perhaps the fuel pump? Gaz lines were all changed too yesterday, and we did try with a different gas thank, same result. Got a mechanic that is supposed to come today to check it.

Got the hull cleaned as well, and I'm almost done with the teak job. I love the boat!

Thanks all for the great advice received.

Kendavis: I don't really have pics while sailing, except this short youtube video where we're testing the ST2000 autohelm but you can't see much: http://www.youtube.com/watch?v=54HYO2ukumo , also some pics in the link of my sig at facebook, but all at the marina. I will take more pics eventually.

Edited by - on

Sloop Smitten
Master Marine Consultant

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USA
1181 Posts

Response Posted - 12/11/2009 : 10:24:09

Steve,
That sounds a lot like the problem I had with my Honda. Check out this [url="http://www.catalina-capri-25s.com/forum/topic.asp?TOPIC_ID=15982&SearchTerms=prop"]link[/url]. The one thing that sounds different for your situation is that it throttles back down to almost a stall. That sounds like a fuel mixture issue which can be caused by a number of issues: dirty carb jets, leaky or kinked gas line, bad primer bulb, unvented gas tank, dirty fuel, misadjusted choke, etc.

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 12/11/2009 : 12:35:28

Revving up and then stalling is what an engine does when it runs out of gas. That doesn't sound like a carb problem--more like a fuel line or pump problem. Any tiny leak in the fuel line connectors, at the tank or the engine, will let air get in and break the suction from the fuel pump. I can sort of imagine how throttling back might save it--that reduces the suction from the pump and therefore maybe the air leaking in.

Edited by - on

glen
Captain

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359 Posts

Response Posted - 12/11/2009 : 13:49:40

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Dave Bristle
 Revving up and then stalling is what an engine does when it runs out of gas. That doesn't sound like a carb problem--more like a fuel line or pump problem. Any tiny leak in the fuel line connectors, at the tank or the engine, will let air get in and break the suction from the fuel pump. I can sort of imagine how throttling back might save it--that reduces the suction from the pump and therefore maybe the air leaking in.
<hr height="1" noshade id="quote"></blockquote id="quote">Dave your right about the fuel line I had this problem with an old gas line. The rubber will sometimes soften and collapse, causing the flow of gas to reduce or even stop. After the engine has quit the gas line may return to a normal looking condition. Not saying this is the problem, just adding fuel to the fire

Edited by - on

Sloop Smitten
Master Marine Consultant

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USA
1181 Posts

Response Posted - 12/11/2009 : 15:01:01

The revving up of the engine when you attempt to run all of the fuel out of the carb is due to the fuel mixture going lean as the fuel is exhausted. Sounds like something is starving the fuel so Dave's suggestions are a good place to start. Make sure and check any fuel lines under the engine hood as well as any fuel filters. A bad diaphragm in the fuel pump might also contribute to this. Some fuel pumps have filters built in to them as well.

Edited by - on

Guero
Deckhand

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Mexico
6 Posts

Response Posted - 12/14/2009 : 14:09:00

Well I am not sure what the Mexican mechanic did beside cleaning but my problem is gone! They took the engine for one day, bring it back next and i could rev to the max without any issues.

Now, I'm gonna get on the few leaks under heavy rain. Gonna have to take the windows apart and reseal them from scratch I guess!

And thanks again all for the great advice, appreciated!

Edited by - Guero on 12/14/2009 14:09:42

Sloop Smitten
Master Marine Consultant

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USA
1181 Posts

Response Posted - 12/14/2009 : 15:18:27

Guero,
It would be real helpful it you found out what the issue is and let us know. Could save someone here a repair bill. Sweet you've worked through two engine problems since you've been here. Those window leaks are a real pain. Lots of information in the archives ( past & recent) about that issue. Does it rain much in the Yucatan?

Edited by - on

Guero
Deckhand

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Mexico
6 Posts

Response Posted - 12/17/2009 : 11:23:19

Joe,

I'll try to get more details and try to translate properly this time as to what my mechanic did. But basically, I know that he didn't change any pieces. He did clean everything, including carb, and told me that the filter in the gas pump was clean. But I will try to get the exact details the next time I see him!

I'm still not 100% percent satisfied with the engine, I noticed it sometimes stall on idle when engaged on forward or reverse, so i have to give it a few more RPM to prevent that, I just got a quote for a new Johnson gas pump... I might get it changed in the following weeks.

In regard to the rain in Yucatan, the problem is not that there's a lot of rain down here, but it's the intensity of it. I noticed i get no leaks on a light to medium rain, but under short, but heavy rains, I can sea leaks from 2-3 places inside. So I'm gonna re-seal everything asap.

Edited by - on

Sloop Smitten
Master Marine Consultant

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USA
1181 Posts

Response Posted - 12/17/2009 : 19:14:26

Guero,
I had that same problem (stalling when in gear) with my Honda for three years. I would clean the idle jet and it would be good for a while then the problem would return. Usually at the most inopportune time. I finally coughed up $5 and bought a new jet. Problem went away. I believe the orifices on the Honda jets are so small that any imperfection or debris can starve them enough to stall the engine if a load exists. See if your mechanic can order you a new idle jet.

Edited by - on

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