No power in gear

[Mo]

Excellent point John. Certainly worth a look while he's there at those checks.

[Decca]

back in business

Hey!
First of all, I have to say that I am totally stunned. I didn't expect so many advices and tips so quickly. Very impressive, and I am indeed very thankful.
It took me some time to get back to you guys, but I did some work !

So to go straight to the point: I got some improvement, but it is still not perfect. AND, I don't know HOW I improved it.... well. What I mainly did is that I played again with the carbs, and basically built a 3rd carb out of the 2 I had taking from each of them the parts that looked best, and putting them together with new gaskets, and did what Ndutton suggested (clean the flame arrestor again, oil the flyweights) and I also checked the prop myself (free and clean). Also checked and cleaned fuel lines and filter, all clean and flowing well, and I cleaned the fuel filter again anyway.
After all that, I went out sailing (as Lat 64 mentioned it, some of us ARE SAILING IN WINTER! but it is easy to do so when it is 70+ degrees outside and sunny ) and it... worked! I could reach 6.3 knots under power (it was only 4 knots before) and reach up to 2100 rpm, while idling at 800. Good idle, good power, good acceleration, and this was in quite heavy seas. Not really GOOD, but better. I think I have 75% of the power now. How I did it I have no idea, maybe the carb after all... maybe a combination...?

Anyway, 75% just isn't good enough, I want it all! So I'll keep working on it. It is actually not so much to get the extra power (now with 75% I feel safe enough) than to keep my engine healthy. He can do it, but he is clearly telling me that he is still not totally healthy and I want to take care of him

So let's keep going:
Here are a few answers to the questions I received.

- the plugs are set up correctly. I know this because the PO was the first and only owner, and he was very very meticulous. Everything he did, purchased, or noticed related to this boat since 1983 is documented and kept. I have a diagram of how the plugs should be wired.

- the history of the engine is as follows: worked fine until last summer. Was left without being used for a couple of months by PO when I purchased it. Power issue was there since day 1 (well, I didn't pay much attention to it on the very first day, but at least from day 2). The owner had similar issues that were always solved with change of plugs and MMO, which I did. Twice.

- the prop is clean. I don't know about it's size, but it is the same prop the PO used without any issue previously. I dived under the boat and it's all clean, all good.

Out of the suggestions that came, I really liked the 2 following (because they are easy to check ) and will check them.
- the stuffing box (John could you tell me where to find it? You say " unscrew the packing glan"? I really know nothing about engines, and if you could be a little bit more detailed about where to locate this thing...)

- the shift linkage. Never thought of this. Thanks, John (the other John). Will give it a check. I'm praying for it to be the issue, that would be so so great.

However, I have the terrible feeling that Mo and Ndutton are 100% right and that I'll soon have no other choice than considering the exhaust. I also have to admit that however the PO was very careful, after 30 years the engine is kind of heavily rusted and small rusted parts are falling everywhere. Therefore I wouldn't be surprised if rust were to be found in the exhaust, as I found rusted parts pretty much everywhere else (on the ground, in the flame arrestor, around the plugs, ...)

Again, thank you all for your help, I feel like I just had a team of skilled mechanics come to my boat, and it feels great!

I WILL TAKE SOME TIME TO COME BACK TO YOU, because I'm not on the boat anymore (holidays, visiting family!) and won't be for the next 3 weeks at least. And then, I'll be do a passage ( a slow, coastal cruising, farniente passage) from Panama city to Tampa, FL (70 degrees just isn't enough. I want warmer! just kidding). Once I'll be in Tampa, I'll get back to work, and let you know how it goes.

Cheers
D.

[Sony2000]

Before going too far, what are the mixture settings on your carburators? Like 1 1/2 turns out from being "in".

[ndutton]

2100 RPM and 6.3 knots? Dude, that's all I've ever wrung out of mine. Assuming your prop is the typical diameter and pitch I think you're already there. I'd run it for a while and read the plugs, maybe make minute adjustments as the plugs indicate.

For reference the theoretical hull speed is 6.7 knots and that's in a dead flat calm; the factory Catalina 30 prop is 12x7x1 RH two blade.

[yeahjohn]

I dream about those numbers... I max out at 1600 rpm and 5.5 knts with my martec folding prop. The stuffing box is where the shaft goes through the boat and into the water, it is the covered area right below the companion way ladder. The shaft is there, along with the shaft log (piece of tubing), and packing gland (the nut thing, with a lock nut). I would not mess with it until you can ask a dock neighbor who knows how to help you. This stuff is rather important because if it fails your boat will sink. Google proper maintenance etc.

[JOHN COOKSON]

Decca
I reread this thread. I'm going to join in with the others that say after you have tried all of the other fixes and you are still not getting all the power you should it is time to look at the exhaust system.
Rubber exhaust tubing can collapse internally and still appear normal on the outside. There are many Catalina 30 owners in the forum that will be willing to help with the project. You are not alone when you are in the forum.

TRUE GRIT

[Mo]

I think you have it.

If the engine is pushing the boat at 2100 / 6.3 kts in calm water I think you are there. It won't go faster. Neil has the same boat as you. Mine is a C&C 30 and I'd be lucky to push it at 6.2 with clean bottom and dead calm...that's all there is.

[edwardc]

Decca,

With a 25' waterline, the theoretical hull speed is of the C30 is only 6.7 kts (1.34 x sqrt(LWL) ), so you're essentially there, as it takes increasingly large amounts of power as you approach hull speed.

But I had another question. How exactly are you judging or measuring "power"? You can't do it by the percent of the max throttle position, as our A4s have a carb that is capable of supplying a much larger displacement engine than we have (I'm sure Dave Neptune can give much better details). Once the engine is taking all it's capable of, there is no effect from applying further throttle. Even in a perfect A4, there will always be some "unused" throttle beyond the max RPM setting. This is normal, and not indicative of an under-performing engine.

[Decca]

well, good to hear that I get some good figures, however here is my concern: I am aware of the hull speed limit and I do not expect to go faster. I expect to have extra throttle power. Right now, I can carefully reach the 6 knots after playing with the throttle, but still, it is not responding "very well" (sometimes I move the throttle up and there is no answer, then it decreases a little bit, then it increases again), and also I do not have this "extra power" that could be necessary if I had a strong current against me or other challenging conditions. The max I get in RPM barely gets me to this speed of 6knots, and then it is impossible to increase the power.

I did my homework and read that to bring a catalina 30 to hull speed an engine has to develop 10HP. So with 30 HP I should have plenty of extra power (not extra speed, I know) that I don't have.

Does it make sense? Do you still think that I have unrealistic expectations and that I cannot really get better than what I have right now?

[Bold Rascal]

30Bhp

Hi Decca, Here's a cut N paste from an A4 manual PDF I found online a while back. I hope it post's correctly for you but according to the information available, 30BHP is not achieved until 3500 RPM.

Brake Horsepower
RPM 600 1000 1500 2000 2500 3000 3500
UJS-UJSR 4 7.1 11 15 18 — ---
UJ-UJR-UJVD 5 7.3 11.9 16.2 20 25 30

I'd be really happy to get 6 knots even in calm conditions. Maybe this year.

[Bold Rascal]

yep, thought it would do that..

So much for cut N paste.
RPM BHP
600 4/5
1000 7.1/7.3
1500 11/11.9
2000 15/16.2
2500 18/20
3000 --/25
3500 --/30

[JOHN COOKSON]

Decca

IMO you are on the right track. Keep at it until YOU are satisfied with your engines performance. The advice of others is fine but you are the one that needs to be happy in the end.

It is not a good feeling to be out on the ocean and have doubts about yourself, your crew, your boat, your engine, your anything. If you have doubts don't go. You will have a safer more plesant cruise if you don't have any doubts before you leave.

Now back to business: I didn't reread the thread. What size prop do you have? You may be over propped.

TRUE GRIT

[Sony2000]

My boat was possibly referred to by Mo, as being the one that was overproped. Max rpm was 1100 at the time and I believe the PO from 5 years earlier, operated the boat like that. So I went from the 12X9 I think, to the plastic one that is 11X7, while the boat is on the hard this winter. A rough estimate is that I can expect a 3"x200 rpm=600 rpm increase, this Spring.
Since you are afloat, do check that each cylinder is firing when under load.

Follow up: The CDI prop has raised my RPM to a comfortable 1600 rpm, and I feel it could easily go higher.