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Posts: 485
Location: On my favorite lake! | My friends boat dies when the motor is trimmed down but runs fine when trimmed up. Has anyone had any similar circustances.
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| Mine does the same thing. When slightly trimmed up it runs at slow idle fine, but when trimmed all of the way down, it starts to 'chug' like it is carboned up?
Interested in anyones thoughts as to why this is happening. |
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| Possible the fuel line is getting pinched? |
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Posts: 550
Location: So. Illinois | Is this an outboard or is an I/O with a lower unit? If it is an I.O, your coupler between the engine and lower unit could be worn or it could lack lubrication. When it is trimmed down, it might be creating a load that is killing the engine. |
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Posts: 273
| Pinched fuel line was my first thought also. Another is a broken float in the carb. Give us some more info about the motor please. I am up for a good brain teaser in the dead of winter.
Jeff |
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Posts: 485
Location: On my favorite lake! | This is an Outboard. I checked the fuel line and it isn't pinched. Could it be air that could be getting in somehow?
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Posts: 485
Location: On my favorite lake! | This is a 1986 150 evinrude. |
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Posts: 5874
| My thought is that the floats are sticking when it is trimmed down, and it's getting too much fuel. |
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| My motor is a 175hp Yamaha Pro V- 1994. Runs great, but again about the only time it 'chugs' or runs rough is when you are at slow idle and trim the motor all the way down...it even seems to throw more exhaust during this time. I don't think the fuel line is getting pinched...Only started doing this the past couple of years.
Also, another question: What can cause the plugs to carbon up (I never troll with this motor)? I have been changing my plugs at the start of the season and at mid-season thinking this may have something to do with the problem. When I change them at mid-season they are seem a bit carboned. The motor does seem to run smoother for a awhile with the new plugs; maybe just my imagination?
Any ideas? |
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Posts: 134
| Excess exhaust and fouled plugs = too rich fuel to air ratio; your burning too much fuel, have it adjusted by someone that is qualified to do so.
Joe W |
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Posts: 177
Location: Cohasset, MN | I had a 1990 Johnson 150 that sat low to the water on a bass boat. When trimmed all the way down the exhaust relief port (If that's what the proper term is) would be just under the water line. This back-pressure seemed to make it harder to start and it would frequently die when at idle. I'm no mechanic and don't know if that's the actual "cause" but it was my "fix" (to keep the exhaust port out of the water) for that minor nuisance. |
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Posts: 102
Location: Bowling Green, KY | Most carbureted outboards don't like to idle with the motor trimmed in the hole shot
position (tucked all the way under). I think this problem is aggravated by cold
dense water. All these increase back pressure on the exhaust coming through the
center of the prop. I'm pretty sure the small exhaust port just below the cowling
is just for "overflow" exhaust. Over the years I've just got where I don't ask them
to. My outboards never get trimmed all the way down till just before I drop the
hammer. |
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Posts: 485
Location: On my favorite lake! | Thanks guys for your help. I will check out your posts and start elimanating one after the other. |
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