Engine power issue

Jul 23, 2009
857
Beneteau 31 Oceanis Grand Lake, Oklahoma
Smokey, 30% minimum is the manufacture recommendation.

jonelli, what type of folding prop do you have?
 
Jun 2, 2014
589
Catalina 30 mkII - 1987 Alamitos Bay Marina, LB, CA
Not sure of the make/model of prop. I’ve got a picture somewhere.

I’m at the boat today, about to start messing with it. I pulled the air filter (sponge) out and ran the motor and made no difference.
About to change the filters and fluids. Bought some Lucas injector cleaner that I’ll fill the bowl with after I change everything. I’m doing all this alone and am by no means an expert or a proficient mechanic, so any other advice would be great. I will probably be working on this all weekend.
 
Jun 2, 2014
589
Catalina 30 mkII - 1987 Alamitos Bay Marina, LB, CA
Recap: air filter removed=no difference.
oil change=no difference
Fuel filter Change and Lucas injector cleaner added to primary filter bowl=rough to start and run at first, let it run for about 15-20 min at 1200rpm, ran WOT neutral=same, forward gear WOT=2075 RPM, reverse=2400.
so, with the filter change and injector cleaner added, I gained about 175 RPM improvement.
Im going to fill her up and add some injector cleaner to the tank now and let her run for a bit.
 
Jun 2, 2014
589
Catalina 30 mkII - 1987 Alamitos Bay Marina, LB, CA
Well, no difference. It’s back to 1900rpm in gear. I’m at a loss. I think I’m going to have to pull the mixing elbow. Looks like I’ll need to remove the counter to do that, no?
 
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Apr 5, 2009
2,774
Catalina '88 C30 tr/bs Oak Harbor, WA
I had no problem removing the mixing elbow on my 88 C30 just through the hatches. No need to remove the cabinet. The top hatch is in two parts. The forward half lifts off and the aft half slides out from under the sink cabinet. When replacing it, you will need to hold the vented loop to the side to fit into a slot I the lid.
 
Jul 23, 2009
857
Beneteau 31 Oceanis Grand Lake, Oklahoma
At full throttle in gear does it smoke?
I think it would if you had an exhaust restriction.
 
Jun 2, 2014
589
Catalina 30 mkII - 1987 Alamitos Bay Marina, LB, CA
At full throttle in gear does it smoke?
I think it would if you had an exhaust restriction.
It does not. No noticeable smoke. I’ve read though that it could still be the exhaust elbow with these symptoms.
there’s some black soot on the floor under the elbow area. I’m now wondering if it’s just bad now.
 
Jul 23, 2009
857
Beneteau 31 Oceanis Grand Lake, Oklahoma
I'm not familiar with the M25XP so I cannot give you specific instruction.
Basically you disconnect the fuel pump output and direct it onto a container. Run the pump for a specific time and measure the fuel in the container. Does it meet specification?
 
Jun 2, 2014
589
Catalina 30 mkII - 1987 Alamitos Bay Marina, LB, CA
I'm not familiar with the M25XP so I cannot give you specific instruction.
Basically you disconnect the fuel pump output and direct it onto a container. Run the pump for a specific time and measure the fuel in the container. Does it meet specification?
Got it. I will need more info obviously to figure that out and will check that eventually. I feel though that based on everything else, and the bad fuel consumption to get it to 2000rpm while motoring, and everything I’ve read about the mixing elbows, that it’s the elbow that is the most likely cause. Again, I’m no expert, but it seems to make sense. I do run the engine idle to charge a lot while on a mooring overnights, and there was black soot sprinkled around under that area of the elbow. I’ve got a secondary fuel filter mounted to the sliding wood cover that would need to come out to get to the elbow. I’m going to start a new thread just for that. I have a lot of questions about the elbow now.
 
Apr 5, 2009
2,774
Catalina '88 C30 tr/bs Oak Harbor, WA
If it is like mine, the elbow is made from black iron gas pipe and fittings. The "mixing" part is a short pipe welded into a close nipple. When I did mine, everything was in good shape except for some buildup. I cleaned it out and reinstalled. To remove it, you will need to remove the exhaust flange and you will need to replace the gasket at least. I was lucky and careful and it came off without any damage but others have broken the flange studs and/or the flange. It is also a very good idea to install a hump hose to isolate the engine vibration from the water-lift to prevent damage to it. Exhaust System
 

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Jun 2, 2014
589
Catalina 30 mkII - 1987 Alamitos Bay Marina, LB, CA
If it is like mine, the elbow is made from black iron gas pipe and fittings. The "mixing" part is a short pipe welded into a close nipple. When I did mine, everything was in good shape except for some buildup. I cleaned it out and reinstalled. To remove it, you will need to remove the exhaust flange and you will need to replace the gasket at least. I was lucky and careful and it came off without any damage but others have broken the flange studs and/or the flange. It is also a very good idea to install a hump hose to isolate the engine vibration from the water-lift to prevent damage to it. Exhaust System
That’s good to hear. Not sure what mine is made of yet. I’ll keep my fingers crossed I can do the same. I probably can’t get to it now for another week.
 
Jun 2, 2014
589
Catalina 30 mkII - 1987 Alamitos Bay Marina, LB, CA
Found my problem! Turns out my engine stop cable was McGuyver’d and failed in a way where it wasn’t totally opening back up fully.
so, I’m going to replace it. Does anybody know if the 20’ one that Catalina direct sells is already the correct length?
DBD02D91-0BA8-447E-A5AF-D1BDDE68C703.jpeg
 
Jun 2, 2014
589
Catalina 30 mkII - 1987 Alamitos Bay Marina, LB, CA
After some thought, the statement on CD’s website (may be trimmed to fit) makes me think that’s how this got that way. It was likely replaced and was never properly terminated. The cable overall looks okay, it just needs a proper ferrule on the end. id like to explore fixing the end first.
Can’t believe this was my issue all along. It makes total sense how the engine ran fine till I stopped it and restarted. And now it starts right up like normal. Crazy...
I’m glad you guys made me check the exhaust elbow though. One less future failure to worry about now.
 

Ward H

.
Nov 7, 2011
3,645
Catalina 30 Mk II Barnegat, NJ
I was following this thread as I have the same engine. Agree with SyconeDriver, great find.
 
Jun 2, 2014
589
Catalina 30 mkII - 1987 Alamitos Bay Marina, LB, CA
Yes. It was insane. Now tied up at the slip I can get up to 2600-2700 or higher RPM in gear. I was getting 1900-2000 before. It was immediately obvious that this solved the issue.
It explains why the fuel pump tested fine, the in/out air made no difference, and why sometimes it went a little more or less on max RPM.

I have to give credit to my friend. He came over to help me do a last go-over on this motor issue, brought a compression tester and digital tach. I was showing him the throttle mechanism and he noticed the fuel stop cable going through the bracket like that and said “what’s going on here?” And the rest is history.
We high five’d, cracked a beer and celebrated.
 
Mar 9, 2020
28
Catalina 30 MkII Oyster Bay NY
Yes. It was insane. Now tied up at the slip I can get up to 2600-2700 or higher RPM in gear. I was getting 1900-2000 before. It was immediately obvious that this solved the issue.
It explains why the fuel pump tested fine, the in/out air made no difference, and why sometimes it went a little more or less on max RPM.

I have to give credit to my friend. He came over to help me do a last go-over on this motor issue, brought a compression tester and digital tach. I was showing him the throttle mechanism and he noticed the fuel stop cable going through the bracket like that and said “what’s going on here?” And the rest is history.
We high five’d, cracked a beer and celebrated.
I have the same model - '88 mkII. Its hard to tell whats going on and the condition of the cable, but can tell you that the screw looking stopper on your cable goes on the OTHER side of the lever.

fyi I had my stop cable replaced last season, my boat yard replaced it and they used an LU33 20ft cable, and they had to trim it slightly to fit. It was a 2hr job. Here is a link to the part if you decide to go that route.