| T O P I C R E V I E W |
| Justus3 |
Posted - 05/19/2009 : 7:04:43 PM
Hi and happy boating season to all.
Last season I had new carbs installed and now I'm noticing a small amount of gas seeping past the seals - enough to put a pink film on the carb housings and create a small pool on one of the depressions on top of the engine.
The dealer maintains that this is not unusual and not a cause for concern. I'm not 100% convinced. Any opinions would be appreciated.
Ron |
| 15 L A T E S T R E P L I E S (Newest First) |
| stevenp |
Posted - 06/02/2009 : 7:01:03 PM
quote:
Originally posted by Justus3
Please recognize that I am relaying information from the mechanic and I am no expert on these matters by a long shot.
I believe he recommended that the mechanical pumps should take over from the electric pumps after start-up. That may just have been his preference and I will double check that.
He also said that if the electrics are running all the time they must be wired to disengage automatically if the engine quits for any reason.
It now appears that a previous owner installed one electric pump because the mechanicals, for some as yet unknown reason, could not supply enough fuel. The boat does not run well at all without the support of the electric pump. I ran it up to 3000 RPM last night with the electric pump off and the port engine sputtered and died. It restared and ran sluggishly at low RPMs.
So I am back to square one as far as the fuel pumps go.
Sigh.
Ron
1978 Carver Santa Cruz 28
Vancouver Island BC
No worries, I'm a novice myself. I've had similar problems with fuel delivery which is why I asked. Turns out my problems are carb related though. |
| Justus3 |
Posted - 06/01/2009 : 7:01:22 PM
Great information Brett - thanks. We had the boat out last night with the electric pump and it ran well even at 3500 RPM but I would prefer to have the mechanicals working properly. Ron
1978 Carver Santa Cruz 28
Vancouver Island BC |
| monterey74 |
Posted - 05/31/2009 : 10:24:39 PM
quote:
Originally posted by Justus3
Please recognize that I am relaying information from the mechanic and I am no expert on these matters by a long shot.
I believe he recommended that the mechanical pumps should take over from the electric pumps after start-up. That may just have been his preference and I will double check that.
He also said that if the electrics are running all the time they must be wired to disengage automatically if the engine quits for any reason.
It now appears that a previous owner installed one electric pump because the mechanicals, for some as yet unknown reason, could not supply enough fuel. The boat does not run well at all without the support of the electric pump. I ran it up to 3000 RPM last night with the electric pump off and the port engine sputtered and died. It restared and ran sluggishly at low RPMs.
So I am back to square one as far as the fuel pumps go.
Sigh.
Ron
1978 Carver Santa Cruz 28
Vancouver Island BC
I had very similar trouble with the 302s in my Monterey last summer. One was starving for fuel. Both engines have marine-grade mechanical fuel pumps (dual diaphragms, etc...) and I removed them both and inspected them expecting to find a problem with one of the pumps. Instead I found both fuel pumps to be in excellent working order.
I spoke with a friend of mine who is a well honed auto/boat mechanic. He suspected that the fuel lines may be de-laminated and the inner wall of rubber was constricting the flow of fuel from the fuel tank to the pump. Well, when I cut the rubber fuel line open I found that indeed the inner and outer walls of the fuel line had separated. I replaced all the fuel lines and the problem seemed solved. However once I got the boat out into open water and the fuel demands increased, the port engine once again starved for fuel and stalled out.
To make a very long, tedious troubleshooting story short.... I began inspecting every component in the fuel delivery system starting at the carburetor. Everything seemed fine... ...until I unscrewed the dip tube from the fuel tank. Evidently the port side tube was too long and was sucking onto the bottom of the tank and restricting fuel flow to the fuel pump. I cut a bit of the tube off on a 45° angle and everything has been fine since.
The end result was that a couple small problems were causing a fuel delivery problem to my port engine. The problem had plagued me for so long that I was considering making changes to the system, including the introduction of an electric pump to get the fuel to the engine reliably. Once the root cause of the fuel restriction was found, however, the electric pump became unnecessary.
I have to wonder why the previous owner decided an electric pump was necessary on your boat. These boats require the fuel pumps to raise the fuel __at most__ a couple feet from the tank. A mechanical pump should have no problem doing this as long as there are no restrictions or leaks in the fuel line.
My advice is to verify the efficacy of your mechanical fuel pumps, check that the fuel lines are not restricted or leaking anywhere, check that the anti-siphon valve where each fuel line connects to the tank is working properly, and check the dip tubes. It often helps to swap fuel lines port <--> starboard to help isolate a problem. Electric pumps should not be necessary on your boat and simply open up a whole set of new problems. If the electric pumps run only until startup, then they are only serving to prime the mechanical pumps. If your mechanical pumps are losing their prime when the boat is not running it is likely a result of a leak in you fuel line or filter somewhere. I feel that the addition of an electric pump to the system will only be masking the root cause of the problem, likely something very simple.
Brett
1974 2885 Monterey
1978 2896 Mariner (Parts Boat) |
| Justus3 |
Posted - 05/31/2009 : 3:10:17 PM
Please recognize that I am relaying information from the mechanic and I am no expert on these matters by a long shot.
I believe he recommended that the mechanical pumps should take over from the electric pumps after start-up. That may just have been his preference and I will double check that.
He also said that if the electrics are running all the time they must be wired to disengage automatically if the engine quits for any reason.
It now appears that a previous owner installed one electric pump because the mechanicals, for some as yet unknown reason, could not supply enough fuel. The boat does not run well at all without the support of the electric pump. I ran it up to 3000 RPM last night with the electric pump off and the port engine sputtered and died. It restared and ran sluggishly at low RPMs.
So I am back to square one as far as the fuel pumps go.
Sigh.
Ron
1978 Carver Santa Cruz 28
Vancouver Island BC |
| stevenp |
Posted - 05/30/2009 : 11:16:38 PM
quote:
Originally posted by Justus3
Fourth - Electric fuel pumps must be wired so they do not run after start-up.
Are you saying that the electric fuel pump should not be operating once the engine is running? If so, how will fuel be delivered to the engine while it's running? |
| Justus3 |
Posted - 05/23/2009 : 10:11:23 AM
Quite right - I meant to say air intake. Flame arrestors are in place.
Thanks to all for your respnses. Had I listened to the first two mechanics I spoke with a very dangerous condition would not have been uncovered.
Ron |
| BillMiller74344 |
Posted - 05/22/2009 : 11:49:50 PM
Justus3, you made a statement about leakage at the air filters. I hope that was just a misstatement on your part. Marine gas engines are fitted with backfire flame surpressors, not air cleaners. Be sure you have a CG approved flame arrestor on each carb.
wam |
| Jimbo Song |
Posted - 05/22/2009 : 6:47:46 PM
Fantastic! I am really relieved you found the problem and the solution.
Happy, Safe Boating!
quote:
Originally posted by Justus3
Carb update. Well the mechanic is on the case and has made several discoveries.
First - carborators have to be installed level or close to level. The 302's are on at least a 15 degree angle and that is way too much for the floats to work properly. Levelling wedges are on the way.
Second - some of the fuel was seeping from three poorly sealed manifold bolts.
Third - Edlebrock carbs cannot tolerate more than 6 psi of fuel pressure. Electric fuel pumps especially can create too much pressure.
Fourth - Electric fuel pumps must be wired so they do not run after start-up. Also, one fuel pump should never be used to feed two engines.
Ron
1987 Carver Voyager 28
Jimbo Song |
| Justus3 |
Posted - 05/22/2009 : 6:33:39 PM
Carb update. Well the mechanic is on the case and has made several discoveries.
First - carborators have to be installed level or close to level. The 302's are on at least a 15 degree angle and that is way too much for the floats to work properly. Levelling wedges are on the way.
Second - some of the fuel was seeping from three poorly sealed manifold bolts.
Third - Edlebrock carbs cannot tolerate more than 6 psi of fuel pressure. Electric fuel pumps especially can create too much pressure.
Fourth - Electric fuel pumps must be wired so they do not run after start-up. Also, one fuel pump should never be used to feed two engines.
Ron |
| Justus3 |
Posted - 05/21/2009 : 4:31:05 PM
Another possible factor - I have one electric fuel pump feeding both carbs. Ron |
| Justus3 |
Posted - 05/21/2009 : 4:26:08 PM
More gas had seeped from the SB carb overnight and I only ran the engines for a couple of minutes yesterday!
They are new Edlebrock carbs and yes, as I recall, one of the old carbs did have a similar leak. I have re-torqued all the screws - none were loose. Today I noticed that at least some of the leakage seems to be coming from the top of the carb (at the air filter seal).
Believe it or not the mechanics were from two different marinas. I too am amazed at their attitude.
All of your suggestions and warnings are much appreciated. We won't be using the boat until this is resolved.
Ron |
| Jimbo Song |
Posted - 05/21/2009 : 08:17:05 AM
Justus, a couple of questions:
1) Did your old carb's leak like this?
2) Are these new or rebuilt carb's?
3) Have you tried simply re-torqing the screws where it is leaking?
4) Do all three mechanics that gave you this "opinion" work for the same marina? (If they do I'd like to know the name of it so I can make sure I never ever go there for work or service)
I am agast that any competant mechanic would tell you that leaking raw gas in the ER is normal.
quote:
Originally posted by Justus3
Thanks for the suggestions so far.
There are two issues. One: what is causing the leekage and Two: does it present a hazzard.
I have spoken with three different marine machanics now and I am surprised by how unconcerned they all were about the presence of raw gas. Common sense would seem to dictate that no amount of gas leekage is acceptable. So that part of the story still confuses me.
I spoke with Edlebrock and they suggest that high fuel pressure is the most likely cause. Anything over 7 psi would force gas through the gaskets. They also said that overheating might be involved. It is interesting that it is happening on both engines.
Anyway, the mystery continues and I would appreciate any more comments or ideas.
Ron
1987 Carver Voyager 28
Jimbo Song |
| BillMiller74344 |
Posted - 05/21/2009 : 12:04:08 AM
Just to add my two cents. Any gas seepage is too much. The result will be a disaster. I have the same setup on my Carver and have not had fuel seepage past the float bowl gaskets. You need to replace the gaskets every time the float bowls are removed. What ever, don't operate with a fuel leakage or we may read your obituary on this web site.
Bill
wam |
| Justus3 |
Posted - 05/20/2009 : 9:23:05 PM
Thanks for the suggestions so far.
There are two issues. One: what is causing the leekage and Two: does it present a hazzard.
I have spoken with three different marine machanics now and I am surprised by how unconcerned they all were about the presence of raw gas. Common sense would seem to dictate that no amount of gas leekage is acceptable. So that part of the story still confuses me.
I spoke with Edlebrock and they suggest that high fuel pressure is the most likely cause. Anything over 7 psi would force gas through the gaskets. They also said that overheating might be involved. It is interesting that it is happening on both engines.
Anyway, the mystery continues and I would appreciate any more comments or ideas.
Ron
|
| Jimbo Song |
Posted - 05/20/2009 : 1:05:29 PM
It is most certainly NOT normal and is a huge hazard. All it would take is one tiny little spark to cause a very impressive explosion. it doesn't take much gas vapor at all to make a big bang.
Raw gas anywhere in the ER should be addressed immediately.
quote:
Originally posted by Justus3
Hi and happy boating season to all.
Last season I had new carbs installed and now I'm noticing a small amount of gas seeping past the seals - enough to put a pink film on the carb housings and create a small pool on one of the depressions on top of the engine.
The dealer maintains that this is not unusual and not a cause for concern. I'm not 100% convinced. Any opinions would be appreciated.
Ron
1987 Carver Voyager 28
Jimbo Song |
