1986 evinrude 150 engine woes,got some questions

mushman

mushman

Junior Member
I put the boat in on fri,ran great on muffs, took it out last night ran good, no issues.Today we went out opened it up a little more ran great till I let off the throttle a little, then I noticed it was bogging down every once in a while.I opened it up again and it really started to bog and run rough.I noticed the rpms were getting lower and lower, if I pushed on the throttle I got no power out of it.I headed back to the marina at around 2700 when I hit the wake zone at low rpm the engine was shaking alot more than usual.
Yesterday morning I changed the fuel water separator, changed the plugs from ul77v gapless to jjc4 gapped at .30 inches, put in 5 gals fresh fuel on top of the 5 I put in thu, there's about 20 gallons old fuel in there too.
I ran a compression test back at the dock and all cyl are @ 90-94,spark plugs had some w oil, some dry, and one w black crud on it.She starts up easy,but runs rough as I said before.I mix gas and oil, but it still goes through the vro.
Any ideas?.
I have a can of valvetech decarb that I bought last season should I give it a try?, I mix omc decarb(since the engine was rebuilt in 2001),and the green seastar or whatever it is ethanol treatment on every fuel up,along with the evinrude 2 stroke oil.
 
What was in the old fuel filter you changed out? Sounds like you need to drain teh carbs out first thing and go from there. Sounds liek there slimed over with water from your description.
 
I never checked,I just replaced it, then it fell over in the cooler I had put it in.Should I remove the new filter and see whats doing in there?.
I have the engine manual on the boat, and I will go down there in the am, after draining what should I do?should I try running it, should I drain some or all gas from tank?.I read adding seafoam to gas might help remove gunk is that a good idea?.

Forgot to add, when she starts up it runs 300-400 rpm lower at idle,it does start up right away though.
 
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I went out today and bought a new fuel filter,and some 5/16 fuel line.I ended up replacing all the lines up to the ones attached to the carb that I couldn't get to without removing them.I also drained the carbs,I tried to catch as much fuel as I could.I didn't find much of anything in there.
I also pumped about a pint from primer bulb into a glass jar, but didn't see any water.when I looked at the old fuel filter I did find a lot of grit in there.I never replaced it since the rebuild so it's been there a long while.
I ran the engine and it seemed to be running good,no bogging and idle was right on.I looked at the plugs all had oil on them.
Tomorrow I'll get some 3/8 and a fuel bulb and replace the rest,the vacuum hoses are cracked allover do I need to worry about them?,if so any idea what size they are?.
while at the evinrude dealer I asked if there was any spray type carburetor cleaner for outboards,he pointed me towards the CRC Marine Carburetor Cleaner,Merc Power tune,I bought the CRC since the Merc stuff seems to be a deca, but didn't use it.Is that stuff safe for outboards?,I asked if it removed oils he said it was ok.
would Seafoam be good to add to fuel as a carb cleaner?.
 
Using Seafoam in the proper proportions will never hurt your engine. (And it just might help). Personally, I use it in every 5th tankful, just to be on the safe side.
 
Thanks, I'll give it a shot also.Today I changed out the fuel line from water sep to engine,a new primer bulb and line from bulb to sep.I used a can of decarb and it seems to now be running nice at idle.
I took it out for a ride, it still runs a little rough in gear@ 5mph, after I got out of the wake zone I got it up on plane gradually, and it seemed to be running nice, but if I try to get up from slow to stop I get nothing, I can have the throttle all the way down and the boat just doesn't respond, it seems to vibrate too.
I did notice the throttle is very hard to push like it needs grease or something, but it was like this before this problem started.
Any suggestions?, the stripers are biting, and I'd like to get this resolved.
 
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