vinnie1234
Petty Officer 2nd Class
- Joined
- Jul 7, 2014
- Messages
- 161
Hello all. Some of you may know that I have been tweaking and fussing over my boat trying to work out little bugs. Most recently, fixing a cracked block and manifold, and ignition setup/troubleshooting. Recently I had the boat bog and stall on me, which I felt was likely electrical. I did find some fault with the ignition system, however it didn't seem to make sense to me that what I found would be responsible for the symptoms I observed.
When driving home from work yesterday a light went off in my brain. I may have (maybe - you tell me) figured out a problem that could be causing all of the symptoms I have been experiencing.
Before I get there, I will tell you some things that I have observed and dismissed previously:
1.Once, when I lowered my outdrive (at the dock), I noticed that the exhaust was exiting at the upper gearcase/intermediate seal and a little under water. Hard to tell with all the bubbles. I checked the drive to see that it went down all the way (it did) and dismissed the possibility of a restriction in the lower gear case, as I can observe exhaust exiting at the exhaust ports and at the prop too - just not as much as I expected. I figured that this is no big deal, since for the mostpart it seems to run fine.
2. On two separate occasions when playing with my carb, I noticed that there was water in the choke housing. Since I had also recently repaired water leaks near the choke heat tube, I blew this off as water from the leaks being wicked up the heat tube by convection.
3. After leaks were repaired, I notice that there was a small amount of dripping coming from the exhaust hose just after the manifold elbow.
4. When driving at lower speeds, say 15 - 25 mph , there are no problems. Once at higher speeds - and particularly if we are in rougher water, the engine will sputter periodically, rpms will lower a bit and ONCE (just before I went over the ignition system most recently) it slowly bogged and died.
5. On my most recent outing I noticed water in the bilge, and dripping from the manifold right above the solenoid pack. It was a fairly good leak so it got me thinking again....
So as I was driving home it hit me - exhaust flappers. It made sense because if water was backing up into the exhaust manifold, it would explain most of this stuff.....
BUT.
It seems as though my system is not originally equipped with flappers. It looks to me like the concept is for the water to fall below the elbow, having no need for flappers as gravity and low pressure in the outdrive should do the rest.
So here I am now, considering potential problems to see where to look:
*I have considered that there could be an internal leak in the manifold.
*I have considered that there may be a partial restriction in the outdrive exhaust.
* I have considred that there may be flappers in the system, but I cant see them on a microfische and cant see them in the boat because I am looking in the wrong spot.
* I have considered a flow restriction in the cooling system that may slow the discharge of water at the elbow, causing a dripback.
*I have considered the gaskets in the manifold system that may be allowing water to enter the exhaust before the elbow.
I do have a spare manifold, but it is a dual carb setup and I would have to fix em up before installation, so it may be just as fast to troubleshoot the problem rather than switching parts out.
The coolant temperature sits at around 170 all the time. The spark plugs indicate a perfect mixture. Ignition timing is set tp 1*BTDC at idle and advance works, spark dwell at 32*. New cap/rotor/plugs/wires/points/coil. Battery voltage 13.6-14.5v depending on rpm and acc draw. No water in fuel. No fuel filter restriction. 4 psi fuel pressure.
Now, I turn it over to you guys:
Do you know if there are common problems/places to look in regards to this issue?
Am I barking up the wrong tree entirely? Are there other suggestions that would explain what is going on?
Thank you all for reading my novel. It will not be available in stores.
When driving home from work yesterday a light went off in my brain. I may have (maybe - you tell me) figured out a problem that could be causing all of the symptoms I have been experiencing.
Before I get there, I will tell you some things that I have observed and dismissed previously:
1.Once, when I lowered my outdrive (at the dock), I noticed that the exhaust was exiting at the upper gearcase/intermediate seal and a little under water. Hard to tell with all the bubbles. I checked the drive to see that it went down all the way (it did) and dismissed the possibility of a restriction in the lower gear case, as I can observe exhaust exiting at the exhaust ports and at the prop too - just not as much as I expected. I figured that this is no big deal, since for the mostpart it seems to run fine.
2. On two separate occasions when playing with my carb, I noticed that there was water in the choke housing. Since I had also recently repaired water leaks near the choke heat tube, I blew this off as water from the leaks being wicked up the heat tube by convection.
3. After leaks were repaired, I notice that there was a small amount of dripping coming from the exhaust hose just after the manifold elbow.
4. When driving at lower speeds, say 15 - 25 mph , there are no problems. Once at higher speeds - and particularly if we are in rougher water, the engine will sputter periodically, rpms will lower a bit and ONCE (just before I went over the ignition system most recently) it slowly bogged and died.
5. On my most recent outing I noticed water in the bilge, and dripping from the manifold right above the solenoid pack. It was a fairly good leak so it got me thinking again....
So as I was driving home it hit me - exhaust flappers. It made sense because if water was backing up into the exhaust manifold, it would explain most of this stuff.....
BUT.
It seems as though my system is not originally equipped with flappers. It looks to me like the concept is for the water to fall below the elbow, having no need for flappers as gravity and low pressure in the outdrive should do the rest.
So here I am now, considering potential problems to see where to look:
*I have considered that there could be an internal leak in the manifold.
*I have considered that there may be a partial restriction in the outdrive exhaust.
* I have considred that there may be flappers in the system, but I cant see them on a microfische and cant see them in the boat because I am looking in the wrong spot.
* I have considered a flow restriction in the cooling system that may slow the discharge of water at the elbow, causing a dripback.
*I have considered the gaskets in the manifold system that may be allowing water to enter the exhaust before the elbow.
I do have a spare manifold, but it is a dual carb setup and I would have to fix em up before installation, so it may be just as fast to troubleshoot the problem rather than switching parts out.
The coolant temperature sits at around 170 all the time. The spark plugs indicate a perfect mixture. Ignition timing is set tp 1*BTDC at idle and advance works, spark dwell at 32*. New cap/rotor/plugs/wires/points/coil. Battery voltage 13.6-14.5v depending on rpm and acc draw. No water in fuel. No fuel filter restriction. 4 psi fuel pressure.
Now, I turn it over to you guys:
Do you know if there are common problems/places to look in regards to this issue?
Am I barking up the wrong tree entirely? Are there other suggestions that would explain what is going on?
Thank you all for reading my novel. It will not be available in stores.
