1999 70hp oil in carbs

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tinboat257

Recruit
Joined
May 9, 2009
Messages
1
Ihave a 1999 70 hp Johnson , a nice running unit , except when the boat sits for an extended period of time(a month or so) the oil will build up in the carbs and has to be drained before the engine will start..what can I do to prevent this, besides get out in it more (lol!) Thanks guys and thanks for the board.
Bill
 
O

ob

Admiral
Joined
Aug 16, 2002
Messages
6,992
Re: 1999 70hp oil in carbs

Two things I know of that can cause this.A leaky seal between the oil and fuel portion of the VRO/OMS pump unit is one.The other is a defective vent on the oil reservoir which builds up pressure particularly when ambient temps increase.Had the same issue for a spell before disabling the VRO and using the pump as a 50:1 pumper.It got really annoying having to clear all of the smoke on initial startup after a period of setting out of use.
 
tashasdaddy

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 1999 70hp oil in carbs

i had the same problem, with my 2004 50hp on my pontoon. the oil tank was higher than the carbs. i finally went to premix also.
 
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