Johnson 140HP bogs won't plane over

J

JLOWRYinIL

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Joined
Apr 10, 2005
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I have a '79 Johnson 140HP SeaHorse V4 Model #44STL79R that seems to idle OK but when I take it to the water and try to take off it just bogs down and will never plane over. It seems to free rev in neutral fine with the warm up lever. I bought the boat not running but was told it ran fine summer '03 and was not run last year. I assumed that the carbs just needed cleaned and some new fuel would fix. Plugs have been changed to champions as recommended in this forum. One thing I could question when I cleaned the carbs would be the jets. I did not notice until after both carbs were apart that the two jets in the carbs could be interchanged. I would not think that it would idle as well as it does if I got them switched around in both carbs. Just a thought. Maybe you guys know. Other than that, I don't know what else it could be. Power pack? Is there any way to check. I am almost an hour away from the water so it makes trial and error pretty difficult. I seems to run fine with water jacket so I have to be in the water to test. Maybe you pros could save me some serious windshield time. Thanks in advance
 
D

DJ

Guest
Re: Johnson 140HP bogs won't plane over

A multi cylinder 2-stroke will rev, without load, quite easily even if not running on all cylinders.<br /><br />1. Check compression. All cyl's should be over 100 psi and within 5-10 psi of each other.<br /><br />2. You can check to see that each cylinder is firing by using an inductive timing light.
 
J

JLOWRYinIL

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Joined
Apr 10, 2005
Messages
11
Re: Johnson 140HP bogs won't plane over

Thanks for the response. I forgot to mention that I did check compression and all cylinders checked at around 120. Plugs wires were pulled one at a time and each jumped strong blue spark. I did have two plug wires that when removed did not change the way the engine was running as much as the other two did. But, this info did not help me that much because they were on separate sides and one was on the lower cylinders and one the upper. Therefore, I couldn't even determine carbs or ignition. I'm stumped.
 
S

Solittle

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Apr 28, 2002
Messages
7,518
Re: Johnson 140HP bogs won't plane over

The easiest thing to check is for fuel problems. Make up a spray bottle of pre mix fuel/oil. Take the silencer off of the front of the carbs. Take a friend along and drop the boat in the water and start it with the cover off. Put it in gear and advance the throttle. When it starts to bog down spray some of the pre mix directly into the carb. If it picks up you have a fuel system problem.<br /><br />Your description points to crud in the carbs.
 
J

JLOWRYinIL

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Joined
Apr 10, 2005
Messages
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Re: Johnson 140HP bogs won't plane over

Would anyone have a schematic of the correct carbs broken down that they could e-mail me. The manual that came with the boat shows a schematic of carbs but they are not the same as mine. The cover is off of the manual and I am not sure that I have the correct one. I'm pretty sure that these are the correct carbs on the boat and the manual is the incorrect one. This would help me make sure that I got the carbs back right when I cleaned them. THanks! jlowry@shawneelink.net
 
S

Solittle

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Joined
Apr 28, 2002
Messages
7,518
Re: Johnson 140HP bogs won't plane over

YOu need the correct manual in any case. I got my OMC manual at the Outboard Wizzard.
 
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