No power in gear

[Decca]

Hi everybody,

This is my first post although I have been following this forum everyday for quite a while now! I decided to post as I couldn't figure out the next step regarding my issue just by reading the older posts.

I've got an 1983 Catalina 30 with original A-4 engine 30hp, and the same problem as I could find in a handful of other posts: a power loss in gear only. However, I can't figure out who is the culprit. Have a look at the information below and let me know what you think

Problem: power loss, mainly in forward gear. Getting only 25 to 30% of the power, after that, I push the throttle forward with absolutely no result (and sometimes it feels like the engine is suffocating if I insist too much with full throttle, but not always). Revving up perfectly and "explosively" in neutral, revving up more or less fine (probably 50% to 75% power) in reverse and then simply going out of gear if I go above (not starving, going to neutral by itself). I am mainly concerned with the forward issue, as in reverse I get more than enough power to maneuver.

Additional information: doesn't stall, doesn't die, but systematically requires the choke to start on the first start only (subsequent starts are ok) at the very beginning (for literally half a second, if I keep the choke on too long, then it dies)

Troubleshooting:
- Compression checked, satisfactory result (in the 90 range for the four of them).
- All spark plugs changed (older ones looked ok, but changed anyway). Newer one got some black residue on them pretty quickly, I don't know if this is an important information... I cleaned them and put them back, they still look - and are - new)
- carburetor cleaned and rebuilt. Interesting fact here: I have 2 carburetors, and I cleaned and rebuilt both of them, and I get different results with each of them. The problem remains, but with carb #1 the engine idles at 700 RPM and the max RPM is 1200 (!!!) and with carb #2 the engine idles at 1,200 RPM and the max RPM is 1,800. This got me totally puzzled. I tried to idle at 700 RPM with carb #2 but under 1,100 it simply dies. while with carb #1 it cannot get above 1,200 RPM no matter what I do with the idling screw. What does it mean? I thought about it and I formulated the hypothesis that considering that the "range" of operation of both carburetors is similar (about 550 RPM variation from idle to max power), they probably both are fine, but simply work differently, and something else is probably limitating the RPM range at a delta of 550. What do the experts think?
- fuel filter checked: brand new, no issue, no debris, fuel flowing.
- I checked the prop and shaft: clean, no obstruction.
- I poured MMO in the spark plugs holes, hoping to 'free' a 'valve' ( I have no idea what I'm talking about, I just copied what other people did having the same issue) and in the gas.

What I didn't check yet (among the things that were recommended to check in other posts dealing with this problem) : exhaust system, and fuel pump. Exhaust system, because I know nothing about it, and because it's hard to get there, hard to find replacement, and I hope I can avoid this step (and it was replaced 4 years ago, so I thought that it is a little doubtful to already experience internal collapse). Fuel pump because before buying an expensive new one, I'd like to get some direction.
The symptoms and troubleshooting lead me to a dead end, and I don't know where to look next or how to look (can I check the fuel pump without buying a new one? could it be the fuel pump starving the carb?)

so... any idea or recommendation? I can spend time on it, I can't spend money on it, and my mechanical knowledge is very limited (got the boat a couple of months ago, and before that nada. trying to catch up as quickly as I can...)

Thank you for your help!

D

[Mo]

Just a few more things.

Welcome aboard Decca,
Seems you did a few checks in the right direction so I have a few questions.

- Does it start easy?
- Does it stall when put in forward...or reverse.
- Does it bog down when put in forward or reverse.
- Does it run normally without misses etc in neutral and under load?
- Have you double checked the routing of the wires from the distributer to the plugs?...with two of those backwards it will run but not well.
- Do you know what size prop is on the boat?

Common culprits are:
-valves...ensure compression is checked with a guage, not by thumb method.
-exhaust blockage...yet to be determined.
-prop oversized.

There are a few more things that can do this but they usually end up as combination of problems regarding adjustment.

Regarding "transmission shifting":
- Expect to have to hold in into reverse. If you let go it is supposed to move back to the neutral position. When you pull the handle for reverse you should hear a short wind-up as the reversing gear engages....after that you should feel the boat start to move as the prop moves water.

- As for forward. You should feel an indent as it moves into forward...much the same as a shifter on a manual transmission in a car. At this point the boat should start moving forward and you notice prop moving water. RPMs will depend on the prop size. If the forward gear was slipping your rpms would / should rise and the boat makes less than normal speed.

[ndutton]

For starters I'd check a couple of things that seem to be infrequently maintained if at all. Doing so will eliminate them from the mix and get the maintenance up to snuff.

1. Clean the backfire flame arrester. Soak it in a bowl of lacquer thinner or similar aggressive solvent, brush clean both sides and blow out with compressed air.
2. Oil the distributor advance flyweights. They are located under the points plate inside the distributor, should have both springs intact and move freely.
3. Try throttling up by hand underway with the throttle cable removed from the carburetor and see if there's a difference. You'll need a helmsman and puhlenty of clear sea room.

Now a couple of questions:

• With the engine off and in neutral, does the shaft turn easily by hand?
• At max RPM does feathering the choke make a difference? It'll make a difference but is it better or worse?
• OK, everybody calm down, do you have a PCV system? If yes, I'd remove it at least until the troubleshooting is complete.

[lat 64]

I think it's the reversing gear. perhaps not releasing due to maladjustment or some bits inside are broken.
I'm just being a bit too fast out of the gate with this guess, but iv'e been drinking lots of coffee today.

The only thing we don't really know is the history of the problem. The onset of these things can give good clues. So without that I think the above checklist are the best to start with.

Good post by the way. lots of data to get started with.

Russ

[Mo]

Very possible Russ ... I did mention briefly how it should feel on the boat. If his compression numbers are correct then I would be leaning toward fouled or wrong size prop and Neil's number 2 suggestion (excellent by the way Neil... I didn't think of it but we've had that happen on here before as well).

[Al Schober]

Decca,
Welcome to the forum. Hope we can help! :-)
Sounds a lot like a clogged exhaust. If you happen to have one of the Moyer exhaust flanges with the pressure port, use it & advise. Since you probably don't..
Disconnect the exhaust piping from the manifold - don't have to move it much - 1/2" is plenty - and see if it runs any better. If so, you've found your problem. If not, get back and I'll dream up something different - or suggest the same as Neil..

[Decca]

Thank you all for your answers!

@Mo:
Does it start easy? YES, depends on what you call easy but with a little choke starts in less than 5 sec.
- Does it stall when put in forward...or reverse. NO
- Does it bog down when put in forward or reverse. What does bog down mean? *sorry, english isn't my first language. but I don't think so because whatever it means, it behaves well in reverse and forward except for the loss of power.
- Does it run normally without misses etc in neutral and under load? YES
- Have you double checked the routing of the wires from the distributer to the plugs?...with two of those backwards it will run but not well. NO, and I'll check it in the coming days, as this is something I can do easily. thanks!
- Do you know what size prop is on the boat? NO, I just know it is clean and it was working before with the same prop. I will check when I get the opportunity.

-valves...ensure compression is checked with a guage, not by thumb method.
-exhaust blockage...yet to be determined. Done properly with guage, too lazy to pull out the result sheet but all where between 85 and 95 so pretty darn ok for what I've been told.
-prop oversized. to be checked, will let you know. But it is not fouled, I had someone dive under the boat and he said everything was looking fine and aligned (and it was the guy from the boatyard)


And thank you a lot for the reversing gear explanation, now a lot of things make sense!

@neil

Clean the backfire flame arrester. Soak it in a bowl of lacquer thinner or similar aggressive solvent, brush clean both sides and blow out with compressed air. DONE already, together with the carbs.
Oil the distributor advance flyweights. They are located under the points plate inside the distributor, should have both springs intact and move freely. I'll try to find those, and let you know how it goes.
Try throttling up by hand underway with the throttle cable removed from the carburetor and see if there's a difference. You'll need a helmsman and puhlenty of clear sea room. Did it (singlehanded! and there is no difference.

Now a couple of questions:

With the engine off and in neutral, does the shaft turn easily by hand? YES
At max RPM does feathering the choke make a difference? It'll make a difference but is it better or worse? it is worse. the engine doesn't stand the choke except for starting (for the first few seconds)
OK, everybody calm down, do you have a PCV system? If yes, I'd remove it at least until the troubleshooting is complete. No I don't

@lat 64 : god forbides you're right I really don't want to deal with the reversing gear. Is there any easy way to check? But i would be enclined to think that based on what Mo said, I don't have an issue with the reverse gear. If it is meant to go out of gear by itself if not held as he mentioned, then I have no issue. I'll have to try to power up holding it, but even without holding it, it stays in reverse until 2,500 RPM at least which is fine, and I'm enclined to think that if I were to hold it it would just stay in gear. So what Mo said makes a lot of sense to me.

Conclusion: I'll try the few recommendations (for the reverse: hold it manually and see if it stays in gear, for the power loss: check the prop size, check the flyweights, and if I have to... check the exhaust (but only if I have no choice! removing this thing scares me...!)

I'll let you know how it goes! Thank you all for your responsiveness and for welcoming me in the afourian community

Just for the record, it was wonderfully sunny today so I still took the boat out and had a blast, even with my power loss issue and with all the other little issues I have that's how it is and will always be anyway!

[Mo]

Decca,
You have ruled out allot of things. Do you have an MMI manual from Moyer Marine. Allot of these boats are sold with one aboard...you never know. If not you will be needing one...

The firing order is 1243. I will tell you the set up from looking in over the engine toward the rear of the boat....I'm taking for granted that your engine is flywheel forward. Typically, they are set up as below if the distributor hasn't been moved....before pulling anything off check the route of each first. If number 1 is in a different position other than the 9 oclock area let us know before you change anything. If the no 1 is where I'm telling you (below) check the routing ...very common for 3 and 4 to be mixed up.

"Usually" No. 1 wire is the one toward the 9 O'clock position on the distributer, as you look in over the engine from the front...that wire goes to number 1 plug, most forward on the engine toward you.

No 2 wire is in the 12 Oclock position as you look in from the front and it goes to 2nd plug from front of engine

No 4 wire is next...it's at 3 Oclock as you are looking in over the engine...it goes to the 3rd plug back from front of the engine.

No 3 wire is at 6 Oclock position, closest to you, and it goes to the 4th and rear plug.

So that should be the wiring. If that looks OK remove the distributor cap ... I usually just remove the coil wire and leave the plug wires on doing this little job. Remove rotor button. Now you should see a plate (silver metal color if not too rusty)....there are 2 flat head screws holding it ... these are out on the edge of the metal plate securing it to the distrib...if you have points and condenser don't take the screws out of them or your EI if that is there...leave them where they are and don't move them...it will all go back into place. Once those two screws are removed gently lift the plate...might be a cloth looking thing under there but don't remove it...some still have it ..some don't. The springs will be right in front of you...two small ones. Check to ensure not broken and spray liberally with lubricating oil. Put back together reverse order...double check your wires again if you take them off.

You should ask the PO what kind of performance he got in forward as well. You and Al have both mentioned exhaust and I know you don't want to go there...but that could be the problem. I was just going through the easy stuff first. Usually with the exhaust there are a few problem areas...one is enough to hurt your performance.
-sometimes a blockage in manifold....haven't seen it myself.
-collapsed exhaust hose.
-most common...rust flaking off and blocking the metal hot exhaust.

Accessibility is the major factor in how hard this is going to be to fix the hot exhaust ... if it turns out to be the problem. The actual parts and assembly are not that bad to do...I did mine in 3 hrs. I let go the exhaust hose at the rear of the hot exhaust, took off carb, take off 3 nuts on exhaust manifold, let go small hose from T-stat to manifold....then move the whole manifold and hot exhaust to the right a couple of inches so that it clear the studs you just took those 3 nuts off. The gasket may stay on block or manifold...it might be reusable so try to protect from impact. Move the whole thing toward you, manifold and hot exhaust as one piece...might have to wind it through and turn it etc to get it out....might work just fine for you if it comes to that. Might be best to take some measuments, pics or even build a new hot exhaust just like the one you have before you take it off the manifold...by this I mean take it out of the boat first then build you new one like what you have in front of you, then take the old one off and re-istall the new one.

Reversing Gear:...usually not a major at all. I have a feeling it might be OK if you can spin the shaft by hand when in neutral. It should not stick / hold in reverse though. If you let go pressure it should drop out of gear in 1-2 seconds.

Don't sweat it. But talk to that previous owner if you can and see what kind of rpms he had in forward. I've seen A4's so over-propped they couldn't get out of their own way. We check the things that don't cost money first.

[lat 64]

I am trying to make sense of the difference in performance from forward to reverse. Decca, You said it works much better in reverse, right?
And, the motor revs up "explosively" in neutral?

The over-proped idea(that is to say too big of a propellor) fit this simple explanation.

The reverse gear is a reduction of 1.27:1. This means the engine would always have better rpms in reverse than forward. Does this make sense to others or perhaps is this a non-issue for diagnosis?

I'm only pursuing this line of thinking because Mo, Niel, and Al have covered the engine nicely and I can not add better suggestions there. Keep my ideas in the box with the fishing bait, then throw them out when they get too old and they won't smell up the boat.


Nice to learn that SOMEONE gets to sail in the winter!

Russ

[Marian Claire]

Any history on how the engine ran in the past? Have you tried removing one of the plug wires while running under load? http://www.moyermarine.com/faq/1.1.html Welcome to the forum. Dan S/V Marian Claire

[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.

[Dave Neptune]

How & ?

Decca, sounds like a plugged exhaust or and/or a clutch adjustment to me.
Only one question here now ~~Did it run fine before or did it just start slipping into neutral? Sounds to methatthe engineis running fine as you tried 2 carbs so I would not worry about tune or fuel at this point!
A bit more of a chronology of how it ~the problem(s) came to be noticed.
What have you touched,adjusted or moved?
Yeh,I know more than one question~consider the source~.

Dave Neptune

[ndutton]

It sounds like all the usual culprits have been addressed. After you double check the firing order it's likely time for an exhaust backpressure test. This can be safely done with a pressure gauge in the exhaust flange (the necessary components are found here and here) or you can do a noisy and dangerously noxious running test with the exhaust disconnected from the manifold. Be careful with that one.

Maybe before that try a running test at the slip with the engine in forward gear and the shaft coupler disconnected.

[yeahjohn]

Maybe you have done this but as Neil stated check your stuffing box. Our packing glan appeared to be in good order and turned by hand with engine off but once put into gear would automatically freeze up because the stuffing was more like charcoal. So maybe just unscrew the packing glan and check it out for yourself. We had two mechanics tell us we need a new engine... So triple check the extremely basic. Did you just get the boat or did your engine just develop these symptoms? I had very similar symptoms to you.

[JOHN COOKSON]

Here's another quick and easy thing to check.
Disconnect the shift linkage at the shift lever on the engine and shift by hand.
Maybe just maybe all that has happened is your shift linkage somehow got out of adjustment and you are no longer shifting into full forward.

TRUE GRIT