I have a 94 Honda 9.9 four stroke with problems. It runs rough intermitently. It goes from running fine to chugging instantly. The previous owner had it in for repair but they could not find anything wrong. Has anyone had a similar problem and soluition. Thanks!
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Steve O.
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Mark Smith
My problem was....
I used to own a 8hp 4 stroke honda and mine did the same thing (sometimes) the problem was the carborator I had left fuel in the carb and it had "Gelled" in the intake needle. Had to replace the whole carb $80.00 ran great again!
I used to own a 8hp 4 stroke honda and mine did the same thing (sometimes) the problem was the carborator I had left fuel in the carb and it had "Gelled" in the intake needle. Had to replace the whole carb $80.00 ran great again!
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Richard Owen
Check this out
We put a Honda 15HP on a RIB a few years ago. The probelm we discovered was that it's air intake was too close to the water when the motor was hung on the transom of the dinghy. I would get into the boat and the stern woudl drop. Sometimes it wouldn't start and sometimes it ran rough. We had to add a piece of aluminum to the transom to raise the motor, then had no problems!! ROwen
We put a Honda 15HP on a RIB a few years ago. The probelm we discovered was that it's air intake was too close to the water when the motor was hung on the transom of the dinghy. I would get into the boat and the stern woudl drop. Sometimes it wouldn't start and sometimes it ran rough. We had to add a piece of aluminum to the transom to raise the motor, then had no problems!! ROwen
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Ray Bowles
Tim, After having worked on a ba-zillion gas
motors in my lifetime there are only three systems to look at. Mechanical, fuel and fire. Now if the engine hasn't been using oil to any extent between seasons and the compression is ok you can assume the mechanical is ok. Compression can be checked with a compression gauge, with the spark plugs out, either using the electrical starter or hand cranking. As long as the 2 cyls are within 10# of each other it is ok. If the engine runs ok for awhile like you say and then abruptly misses then I don't think there is any mechanical problem. Now electrical. #1. Start out with new spark plugs of the type suggested by the manufacture. I only use NGK or ND plugs in everything I build including the "race engines" I build for myself and others. They are Japanese plugs and I've never has misfire problems with them under severe loads. Set the gap, anti-seize (lightly)the threads and install. Check the ohms resistance of the spark plug wires to be sure they are good. Very often people pull wires off wrongly and damage the inner core of the wire which leads to misfiring under load. The resistance should be under 5,000 ohms. If not, replace the wires. Now fuel, With the engine warm and idling, adjust the idle air screw for best idle. (not the idle speed linkage adjustment) If after adjusting this mixture screw if the idle has risen too high then adjust the linkage screw to lower the idle. If this doesn't remove the problem you can try to find someone knowledgable on small engine fuel systems if you don't feel comfortable doing this, or, get a Honda service manual, usually under $20 from Honda. These are excellent books and can help the earliest of beginners walk thru a Honda engine. Write back if I can help further. Ray S/V Speedy
motors in my lifetime there are only three systems to look at. Mechanical, fuel and fire. Now if the engine hasn't been using oil to any extent between seasons and the compression is ok you can assume the mechanical is ok. Compression can be checked with a compression gauge, with the spark plugs out, either using the electrical starter or hand cranking. As long as the 2 cyls are within 10# of each other it is ok. If the engine runs ok for awhile like you say and then abruptly misses then I don't think there is any mechanical problem. Now electrical. #1. Start out with new spark plugs of the type suggested by the manufacture. I only use NGK or ND plugs in everything I build including the "race engines" I build for myself and others. They are Japanese plugs and I've never has misfire problems with them under severe loads. Set the gap, anti-seize (lightly)the threads and install. Check the ohms resistance of the spark plug wires to be sure they are good. Very often people pull wires off wrongly and damage the inner core of the wire which leads to misfiring under load. The resistance should be under 5,000 ohms. If not, replace the wires. Now fuel, With the engine warm and idling, adjust the idle air screw for best idle. (not the idle speed linkage adjustment) If after adjusting this mixture screw if the idle has risen too high then adjust the linkage screw to lower the idle. If this doesn't remove the problem you can try to find someone knowledgable on small engine fuel systems if you don't feel comfortable doing this, or, get a Honda service manual, usually under $20 from Honda. These are excellent books and can help the earliest of beginners walk thru a Honda engine. Write back if I can help further. Ray S/V Speedy
M
Mark
fuel line
Check if the fuel line is in the correct direction. We did and it made our Yamaha run a lot better!!! when the flow wasn't interupted by the one way valve in the pump bulb.
Check if the fuel line is in the correct direction. We did and it made our Yamaha run a lot better!!! when the flow wasn't interupted by the one way valve in the pump bulb.
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Dan
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Harvey Small
Aussie Fuel Line
Doesn't the arrow on the rubber bulb point the other way in Australia? Sort of like how now it's summer for you blokes?
Doesn't the arrow on the rubber bulb point the other way in Australia? Sort of like how now it's summer for you blokes?
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Tom Cooper
honda 9-9 problem also check this
One more item to check.when your engine slows down does it pick up again if your raise the engine cover. I had a similar problem .If it runs again after raising the cover .The exhaust has a leak and carbon monoxide is choking your engine,hope this helps. V32 Prologue
One more item to check.when your engine slows down does it pick up again if your raise the engine cover. I had a similar problem .If it runs again after raising the cover .The exhaust has a leak and carbon monoxide is choking your engine,hope this helps. V32 Prologue
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Mark
Hello Harvey
Yep your right. We do everthing back to front. Took me ages to figure out which end to put the motor on and then when I did I think I made a mistake cos I have found the motor works better pushing than pulling the yacht along. Thank goodness they supplied this motor with a forward gear so now is all well. Mind you I am thinking of writng to Hunter to ask if they can put the boarding ladder on the back because it is really hard trying to get on the boat when the waves keep knocking you off the ladder. Best regards from down under( the Kings of the America's cup)
Yep your right. We do everthing back to front. Took me ages to figure out which end to put the motor on and then when I did I think I made a mistake cos I have found the motor works better pushing than pulling the yacht along. Thank goodness they supplied this motor with a forward gear so now is all well. Mind you I am thinking of writng to Hunter to ask if they can put the boarding ladder on the back because it is really hard trying to get on the boat when the waves keep knocking you off the ladder. Best regards from down under( the Kings of the America's cup)
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Frank / MD / H260
Tim...
Please tell us what you found the problem to be and how you corrected the problem. Thanks...
Please tell us what you found the problem to be and how you corrected the problem. Thanks...
B
BART FORD
4 stroke engines
I have a Nissan 4-stroke 5hp with similar problems. the motor spent more time in the shop than on the boat. the shop finally discovered the valves had corbonized and when the motor got hot, they would not seat properly. They cleaned them and it has run fine. I use only premium Amoco gas. It burns cleaner than the cheap stuff. Also, when I come in after a day out, I disconnect the gas line and let the motor run dry. Hope this helps.
I have a Nissan 4-stroke 5hp with similar problems. the motor spent more time in the shop than on the boat. the shop finally discovered the valves had corbonized and when the motor got hot, they would not seat properly. They cleaned them and it has run fine. I use only premium Amoco gas. It burns cleaner than the cheap stuff. Also, when I come in after a day out, I disconnect the gas line and let the motor run dry. Hope this helps.
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