#1
IP: 64.163.88.18
|
|||
|
|||
Loud "clicking" at higher RPMs
Hey All,
Last year I swapped out my old Atomic 4 for a rebuilt one. I got it from a reputable mechanic in Northern California.... I'm fairly familiar with these engines (have done a lot of tinkering and I taking on most repairs with help from Moyer Marine and the internet over the past 10 years)...I was hoping to get some feedback about my current symptoms before going down the rabbit hole of running thru every possibility I find on Google. Currently, she starts like a champ every time (requires little choke), the idle RPM adjust is set to standard, the plugs/wires/coil are like new, the electronic ignition is fairly new, the timing (not 100% sure...I set it for the first time) is good, gas is fresh, carb is new, exhaust and raw water seem normal. Well...when I run her at higher RPMs (i.e. wind dies and we motor a few miles back to our marina), she'll at some point sputter, lose power and a LOUD clacking (electrical spark sounding) noise then will almost die and then I need to back her down to a low RPM and she is fine again. But I feel like she's limping a little. This is hard to replicate because it seems to only happen after awhile under load at higher RPMs. The most suspect aspect of the boat is the DC wiring. Before I rewire the DC circuit, I'd like to have a really good reason as this seems very time consuming. Any thoughts? Thanks in advance... |
#2
IP: 107.0.6.242
|
||||
|
||||
Mixture may be getting lean after hard running. Look at fuel tank vent for possible blockage. Check fuel pressure at carb while at cruise rpm. I have had similar experience. Also, pcv can lean out mixture at high rpm.
|
#3
IP: 76.7.144.132
|
||||
|
||||
Do you have an electric fuel pump? Dan S/V Marian Claire
|
#4
IP: 99.141.136.1
|
||||
|
||||
ignition coil?
|
#5
IP: 64.163.88.18
|
|||
|
|||
Quote:
How does one normally check the fuel pressure at carb while at cruise rpm? Also, can you expand on "pcv can lean out mixture at high rpm"? I have no experience with the pcv. thanks! |
#6
IP: 64.163.88.18
|
|||
|
|||
nope, the original pump.
|
#7
IP: 64.163.88.18
|
|||
|
|||
the ignition coil is about a year old.
the issue would seem to be electrical. there is a loud misfiring racket when it happens. sound like throwing some screws into a fan..then it loses power until i power down and then it runs fine at low RPMs. Last edited by kevin d; 02-11-2013 at 07:20 PM. |
#8
IP: 76.7.144.132
|
||||
|
||||
Good deal. That eliminates the electric pump stuck ball "clacking" noise possibility. Another long shot but it ties in with the lean condition Hanley mentions. http://www.moyermarine.com//forums/s...ead.php?t=3369 So maybe try closing the choke some when it starts to stall. If that does not help at what RPM does this happen? Advance weights sticking?
Dan S/V Marian Claire |
#9
IP: 173.166.26.241
|
||||
|
||||
Fuel pressure can be monitored right at the carb using one of these. http://www.mcmaster.com/#atmospheric...gauges/=lfs4fa This can save a lot of diagnostic grief in the long run.
|
#10
IP: 65.92.161.249
|
|||
|
|||
It sounds like fuel starvation, brought about by vapor lock, or a restriction to the flow, prior to the fuel/water separator.
|
#11
IP: 24.152.131.153
|
||||
|
||||
Reading the description my first thought was as Dan mentioned at the end of his post, faulty timing advance mechanism:
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#12
IP: 199.168.148.136
|
|||
|
|||
It Could Be This
Electricity jumping between the spark plug wires. After the engine is run for a while the insulation could be breaking down and electricity is jumping between plug wires and a plug(s) are firing at the wrong time which results in a knock or a hellish engine sound.
Are you running graphite core or solid core wires? In my experience graphite core spark plug wires aren't worth a crap on a boat. Also have you checked for tracking or arcing between the terminals inside the distributor cap? TRUE GRIT Edit: Kevin: When I read about arcing, sparking, and "loud clacking, electrical spark sounding", as reported in your post #1, I think of something after the coil not the 12 volt circut. Last edited by JOHN COOKSON; 02-12-2013 at 12:58 PM. |
#13
IP: 128.183.140.38
|
||||
|
||||
My first two thoughts were :
- Sticking valve - Distributor advance weights
__________________
@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 |
#14
IP: 98.248.12.160
|
|||
|
|||
fuel pressure gauge
Hanley, there are so many pressure gauges listed in the McMaster link, could you be more specific and tell me which one you used? Also, is this gauge plumbed into the fuel line with a tee as would be for a gas pressure gauge? Or in line, like a flow meter gauge? Did you mount your gauge on the output of the fuel pump, or on the input to the carb or in the middle of the fuel line (rubber or copper line)?
Thanks, Herb |
#15
IP: 64.163.88.18
|
|||
|
|||
Quote:
|
#16
IP: 64.163.88.18
|
|||
|
|||
Thanks Ed, would MMO help with the sticking valve if that is the case? Also, I'm not very familiar with the distributor advance weights. What should I be looking for? Or how would I isolate the issue to them?
|
#17
IP: 64.163.88.18
|
|||
|
|||
Quick questions...
Can someone describe the easiest way to set the ignition timing? And what is the best way to check if the mechanical fuel pump is working properly? Thanks |
#18
IP: 128.183.140.38
|
||||
|
||||
Yes, some MMO in the oil (up to one quart!) and some MMO squirted into each cylinder after each use (or as often as possible) so it can soak between uses is the usual course of treatment for a stuck/sticky valve.
The advance weights and the springs that control them are located in the distributor, underneath the breaker plate. If they get stuck out, that would result in excessive advance which could cause "pinging" and poor running. Easiest way to evaluate them is to just open the distributor and remove the breaker plate and examine them for smooth operation and no broken springs.
__________________
@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 |
#19
IP: 76.7.144.132
|
||||
|
||||
This may answer your timing question. http://www.moyermarine.com/forums/sh...ghlight=timing Dan S/V Marian Claire
|
#20
IP: 64.163.88.18
|
|||
|
|||
Thanks Dan and Ed!
|
#21
IP: 107.0.6.242
|
||||
|
||||
Quote:
Last edited by hanleyclifford; 07-13-2016 at 08:32 PM. |
02-12-2013, 06:39 PM |
hanleyclifford |
This message has been deleted by hanleyclifford.
|
#22
IP: 68.5.194.131
|
|||
|
|||
Clicking
I had an issue like this last year. I tried everything. It turned out to be #4 valve would stick at high RPM'S, At low R's it would free up. I had just the right amount of carbon and varnish on the stem to hang it up.I had to remove the head reem the guide and then I put in the after market valve springs. They are taller and stiffer.Runs well now
|
#23
IP: 65.92.161.249
|
|||
|
|||
I fully agree with seabreeone, but if the power loss is greater than just running on three cylinders, then I would look for fuel starvation.
|
#24
IP: 107.0.6.242
|
||||
|
||||
Whenever a problem like this develops the first thing I do is check the basics: timing, both initial and centrifugal, dwell (even with EI), compression (though such test may not detect weak valve spring), cleanliness and viscosity of oil and engine running temp (both of which can influence valve guides) and valve lifter clearances. Before going too far afield make sure the above are on spec. Because I believe in continuous diagnosis I have added fuel pressure gauge and air/fuel ratio gauges. If things are not allowed to go off spec problems are rare.
|
#25
IP: 64.163.88.18
|
|||
|
|||
I think the first thing I'm going to do is rule out 'electrical' issues.
I'm planning to check timing, coil, spark plugs/wires, quick inspection of DC wiring, etc. I may do an oil change, recheck the idle mixture and will inspect the fuel lines and gas tank vent. Thanks for all your help....any other quick (do first) suggestions would be much appreciated. Cheers! |
Tags |
atomic 4 |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
carburetor Problems - HIGH RPMs | jakecolumbia8.3 | Fuel System | 10 | 10-10-2011 08:58 PM |
Prop shaft alignment or a problem with the crank? Knock at low RPM's | rshearley | Reversing Gear | 2 | 05-30-2011 07:48 AM |
Loss of Power at Higher RPMs. | Greg Kingman | Troubleshooting | 3 | 08-24-2009 04:43 PM |
Atomic 4 Engine RPMs | sailingdude | General Interest | 2 | 08-09-2007 06:59 PM |
Low RPM's Under Load | Jeremy Thompson | Troubleshooting | 7 | 11-18-2005 06:10 PM |