rotorhead22
Seaman
- Joined
- May 19, 2015
- Messages
- 74
I was browsing through fuel issues and ran across a post that was similar to my issue and was kindly asked to start a new thread. Here is the issue that was of interest.
89 Merc 100 fuel problem or? May 27th, 2013, 10:25 PM
I have a frustrating problem and question for any mercury mechanics, or experienced owners. I have spent days perusing this forum, and the greater internet trying to find an answer to my problem with no results.
I purchased a used 89 Sea Ray last fall with the original 100hp mercury 2+2 outboard. The previous owners were not reachable as I purchased it from a small dealer who took it in on a trade, so I am going on no history, but it looks well used.
The motor will start, run for around 10-15 seconds then stall and die. When it runs it seems to run as it should for 10-15 seconds, and if I push the keyed choke it will continue to run, as long as I keep priming it. I can also throttle it up past 2k rpms, kicks in the other two cylinders, and runs great, and then does not stall at all. So in short it will not idle long, it just stumbles out and dies after idleing for a short period of time. Priming the bulb will sometimes work, but only by pushing the key/choke can I keep it idling.
Sounds like a fuel delivery issue doesnt it?
It did look like the previous owner had messed with the carbs before, so not sure all of settings are as they need to be. I have gone through everything I can think of, and from what info others that have posted with similar problems, I have removed all 4 of the carbs, cleaned and soaked them thoroughly in cleaner and rebuilt them. Replaced the fuel line from tank to motor with a new line and bulb. Put in new fuel line and filter in the motor, rebuilt the fuel pump, checked the pump pressure, all as it should be. Did a compression check, all cylinders within spec. Checked the fuel pickup tube in the gas tank, and even cleaned the tank out and it all seems to be flowing normally, with clean fuel. I have checked my idle screws on the top two carbs, and tried resetting them to what the service manual suggests. 1 and 3/4 turns out from a light seat then various small adjustments from there, checked my floats and the needle seat for proper adjustments but none of that has changed anything either. I did notice that the carb jets are .54, I live near Denver at nearly 8000ft and from what I found I should have them replaced with .50 jets, but that should not prevent the motor from idling would it?
I have spent too many hours troubleshooting and trying to figure this problem out and am at my last bit of patience with it, and would love to hear from any of you who may have suggestions as to what I can do next. Any help would be greatly appreciated!"
The attached photo is what I found during my troubleshooting. I should have known better after the lady that we bought the boat from stated that the half tank was only six months old. I added fuel cleaner and preservative and filled it up before our first outing. It wasn't until our fourth trip that the motor would not throttle up and would die very quickly.
89 Merc 100 fuel problem or? May 27th, 2013, 10:25 PM
I have a frustrating problem and question for any mercury mechanics, or experienced owners. I have spent days perusing this forum, and the greater internet trying to find an answer to my problem with no results.
I purchased a used 89 Sea Ray last fall with the original 100hp mercury 2+2 outboard. The previous owners were not reachable as I purchased it from a small dealer who took it in on a trade, so I am going on no history, but it looks well used.
The motor will start, run for around 10-15 seconds then stall and die. When it runs it seems to run as it should for 10-15 seconds, and if I push the keyed choke it will continue to run, as long as I keep priming it. I can also throttle it up past 2k rpms, kicks in the other two cylinders, and runs great, and then does not stall at all. So in short it will not idle long, it just stumbles out and dies after idleing for a short period of time. Priming the bulb will sometimes work, but only by pushing the key/choke can I keep it idling.
Sounds like a fuel delivery issue doesnt it?
It did look like the previous owner had messed with the carbs before, so not sure all of settings are as they need to be. I have gone through everything I can think of, and from what info others that have posted with similar problems, I have removed all 4 of the carbs, cleaned and soaked them thoroughly in cleaner and rebuilt them. Replaced the fuel line from tank to motor with a new line and bulb. Put in new fuel line and filter in the motor, rebuilt the fuel pump, checked the pump pressure, all as it should be. Did a compression check, all cylinders within spec. Checked the fuel pickup tube in the gas tank, and even cleaned the tank out and it all seems to be flowing normally, with clean fuel. I have checked my idle screws on the top two carbs, and tried resetting them to what the service manual suggests. 1 and 3/4 turns out from a light seat then various small adjustments from there, checked my floats and the needle seat for proper adjustments but none of that has changed anything either. I did notice that the carb jets are .54, I live near Denver at nearly 8000ft and from what I found I should have them replaced with .50 jets, but that should not prevent the motor from idling would it?
I have spent too many hours troubleshooting and trying to figure this problem out and am at my last bit of patience with it, and would love to hear from any of you who may have suggestions as to what I can do next. Any help would be greatly appreciated!"
The attached photo is what I found during my troubleshooting. I should have known better after the lady that we bought the boat from stated that the half tank was only six months old. I added fuel cleaner and preservative and filled it up before our first outing. It wasn't until our fourth trip that the motor would not throttle up and would die very quickly.
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