atomic 4 questions

[Cruiser2B]

I am not new to the site...have been lurking for sometime. this site actually helped me choosing my alberg 30. Anyway I have an issue with my A4 and was hoping someone here may have had same issues. BTW onnce A4 is done i will be converting to either an outboard or electric for the few times i will use the engine.

ok, A bit of history first...my Alberg 30 with A4, rebuilt completely by Moyer in 2008. I bought the boat this spring and have had zero issues until now.
following items on boat/engine.....

.has fresh water cooling
.electronic ignition
.indigo 3 blade prop
.new shaft
.fuel a week maybe 2 weeks old. i used a portable 3 gallon tank...no internal tank
. Racor 110 fuel filter assy
. boat was hauled and pressure washed in Feb. prop was clean
.removed and cleaned spark arrestor..no change in performance

anyway, i have always been able to achieve 2500-2700 rpms in foward. dont really cruise there but did have to run the motor that high going through some 6ft chop....that god for the extra power that day!

Anyway last weekend took her out and noticed at start up she was a bit hard to start, usually fires right up. no big deal..once started she kind of surged a bit, this was unusual. After she warmed up all seemed fine. backed her out and headed out. while heading out i decided to just run her up abit to clear things out. I only using run her between 1500-1800rpm. Well at about 1/3 throttle she got to 1800 and would not go past no matter how much throttle...just kinda got that hollow sound from carb. went back to 1/3 throttle and cruised out of the channel no missing a beat at 1800 rpm with ideas running thru my head. Once I cleared the channel i tried reverse....engine reved up to 25-2700 no problem. i did this thinking maybe prop was fouled. no change went back in forward. I decided to pull the choke abit to see if maybe she was starving for fuel....at about 1/2 choke she started to die...too much fuel. choke back in and cruised at 1800 for about 10 more min and finally went sailing. On the way back in she started right up and got me home. Today i went down and looked things over...nothing obvious. pulled the plugs, all looked good a slight tan, # 4 was a bit white when conpared to other 3 but overall fine. drain fuel/water separater, there was some debris but no water.
I asked around the docks and someone asked me how dirty the bottom was? would this have an effect on engine rpm. i can see not reaching same speed if bottom was dirty but engine should rev, correct? he told me his boat(alberg 30 with A4 -2 blade prop) wont go over 16-1700 rpm ever.

i ordered a new filter for Racor...nobody in Norfolk area stocked it...

Any ideas on where to look next? is it posssible the bottom is that dirty already? water here is very dirty, cant see 1inch below waterline. i  might call a diver to check things out....will be about 75 to have it cleaned..Could it be timing?

any and all ideas welcomed

Thanks Sailfar

[Mr. Fixit]

I am not a mechanic--however if you have rpm's in reverse i do not see how it could be timing--if you have rpms in reverse and not forward could the problem be in the tranny???something that would cause friction in forward and not in reverse??

[Cruiser2B]

yes, it is possible for sure, it just get to cruising rpm so easily, 1/4 to 1/3 throttle and i am at 1800 rpm (5.2knots), just wont go past there. I am open to all suggestions. I am going to look for a simpler fix than the trans first....with my fingers crossed!

[CaptMac]

Check your prop, I once had a dirty prop and could not get over 1400 RPMS, once cleaned everything was fine. hope it is something this simple, good luck.

[boblamb]

I agree with CapMac...my prop was heavy with barnacles and the rpm dropped 1/2 power.  Scraped it off and away we went.  Hope this works for you!

BobL

[s/v Faith]

Sorry I am coming in late here...
... add my 'yes' to the above.

I once was to make a delivery on a Meridian 386.... it had twin 500+ ci motors... and would not even get on plane.

I put on a mask, and scraped a 'light' accumulation of barnacles off of the props, and that completely fixed the problem.

It does not take a lot of growth to cripple a prop.

Good luck!

[Cruiser2B]

Thanks, i have a diver coming tomorrow. I think i may buy a diving mask a check thing out myself next time. i see guys doing it every wed night at the marina

i will report back

[w00dy]

Interesting problem.

My first boat was a Dickerson ketch that came equipped with a trusty Atomic 4 Medalist. She was in good shape as far as I could tell, though one of the cylinders' compression was a bit lower than the others. Still, she would start right up and seemed to run fine, aside from the time that we filled the gas tank with diesel, but that's another tale...

To make a long story short, we had a very similar issue, which I couldn't figure out how to fix and was one of the reasons I ended up selling the boat. Although we could idle and reach cruising speed, any attempt to throttle the engine up above 1800-2000 rpm would result in misfire, sputtering, loss of power, etc. I know this had nothing to do with the prop because we had just hauled and cleaned it. Also, our engine would occasionally die unexpectedly, as a result of some unknown issue.

I can't count how many times I removed and cleaned the carburetor. I also replaced the wiring, spark plugs, points, coil, and ignition, and fuel pump with parts recommended by Moyer Marine. To this day, I have no idea what in the heck was ailing my engine.

I hope you figure it out and if so, please let me know what the problem was. I just might sleep better at night.

[Cruiser2B]

Diver came out this morning and cleaned prop and bottom. he said bottom looked good but prop had lots of barnicles. $60 bux to clean hull and prop. Not too bad

Took her out for a cruise a bit ago and engine went to to 2300rpm. she ran just fine, started right up. Boat was moving at 6.2 knots....making a wake! I am not too worried about it boat moves ok and this engine truely is just used as an auxillary, I will keep an eye on things.maybe this fall i will look at the carb.

just curious though, Does this seem like normal rpm for this boat and this prop?

thank for the help


jm....i feel your pain. i will not sell the boat because of this issue. all seems fine...the engine does the job of getting me in and out of our marina and still moves the boat along quite well.  if i figure it out i will keep you posted. i sm not going to loose sleep over it. i will pull the engine out and scull the boat before i let this engine make me loose sleep ;D. i will keep her patched up and running but the first time she become unreliable i will consider and install another form of auxillary power

[s/v Faith]

Great!

  Glad that was all it was.

Yes, 6.2 knots at 2300 sounds pretty good.  What you will likely discover if you do some experiments is that you don't want to run it up over 2k for long...

If you can get something around 5 knots (maybe 5.5) at a lower throttle position (maybe just below 2k, or 1900  rpm) you will find your fuel use drips alot.  I mean something like going 1/3 more range for the same conditions...

...  find that 'sweet spot' where the noise is right, the vibration settles down and the motor stays in a good temp range... it is going to help your fuel use alot!

Super glad you got it worked out.  Good job!