120 evinrude boggig down

denndenn

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Jun 5, 2011
Messages
15
I have a 1987 evinrude 120 i rebuilt carbs link and sinked everything changed plugs and when i get on the water first thing in the am the boat takes less time to get on plane compared to later on in the day. As the day goess on it seems that the boats bogs down before getting on plane. I noticed that when its bogging doen that if i turn left sharply and start to run in circles it seems to get on plane faster. Could it be that the motor is on the on the jack plate is to low? Propeller? I have no idea on where or what to look for.
 

Solittle

Fleet Admiral
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Apr 28, 2002
Messages
7,518
Re: 120 evinrude boggig down

Lotsa "could be's". You need to do some troubleshooting and preferably with a OMC service manual. For these engines to run you need to check for compression, spark and fuel. Guessing will just result in frustration.
 

denndenn

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Jun 5, 2011
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Re: 120 evinrude boggig down

ive done compression check have good spark fuel is good if fuel was problem it would not run all day.
 

Solittle

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7,518
Re: 120 evinrude boggig down

ive done compression check have good spark fuel is good if fuel was problem it would not run all day.

What readings did you get with the compression check? And how much of a gap will the spark jump?
 

denndenn

Cadet
Joined
Jun 5, 2011
Messages
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Re: 120 evinrude boggig down

150
150
145
145 on the compression check. I just put a spark tester on and checked for spark and had spark on all cylinders
 

SparkieBoat

Captain
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Aug 17, 2009
Messages
3,643
Re: 120 evinrude boggig down

if timing is good..you have your self a fuel proble..check all lines and connections, check fuel pump, clean the **** out of your carbs.
 

denndenn

Cadet
Joined
Jun 5, 2011
Messages
15
Re: 120 evinrude boggig down

dumped a can of seafoam in gas tank and seemed to fix problem. Gonna follow directions for decarb this weekend. Can anyone tell me is it better to use the deep creep or regular sea foam spray?
 

denndenn

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Joined
Jun 5, 2011
Messages
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Re: 120 evinrude boggig down

well was on the water again today and the evinrude 120 would not get on plane if i didnt turn tight circles to the left. Once on plane the boat was doing 49 mph according to gps. What could be the problem where do i begin checking. Compression is good has spark and obviouly gets gas because i ran it wot for an extended period of time. While running it ran good the problem was getrting on plane. Did have problem starting one time.
 

Sander

Petty Officer 2nd Class
Joined
Aug 8, 2011
Messages
167
Re: 120 evinrude boggig down

Long shot, but test out the fuel pump. The pump could be failing.
 

BonairII

Commander
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Jun 7, 2011
Messages
2,727
Re: 120 evinrude boggig down

What kind of boat is the motor on? Just a wild guess, but could this be a boat prob and not a motor prob?
Have you checked to see if you're taking on water throughout the day?
 
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