Fast strike idle issue

[Mikey N.C.]

Customer brought in 2001 150 osi ,21 hrs ,
customer pulled carbs. to rebuild himself( cause he thought they needed it ???) He said now motor want idle. Took to lake today cranked and warmed up, took off and ran about 1 mile ran like new, hole shot unbelievable . could bring down to 30 mph and throttle open not a problem. Came back to ramp in gear 800 rpm, then motor would start dropping rpm to 600 cough and shut off, crank rite back up , put in gear putting to trailer same thing. Didn't get chance to look at but will tomorrow. Just wondering if y'all have run acrossed this. Or seen this

 

[Sea Rider]

Would be fantastic to know which brand, HP and if it's a 2 or 4 strokes motor to start with..

Happy Boating

 

[racerone]

I think that would be a Johnson V-6 and a 2 stroke.

 

[Mikey N.C.]

My bad it's a Johnson V6 , 6 carbs 150 hp.
I didn't know they made fast strike 4 stroke( did they ?)

 

[flyingscott]

Look.at.the optical sensor. And did they completely clean.the carb by taking all the plugs off?

 

[Mikey N.C.]

I'm thinking this one has has idle air adjustable jet( not fixed) if I'm not mistaken the newer ones had the Allen jet with access hole drilled thru carb. all the way back to butterflies..

 

[Mikey N.C.]

Thanks, flyingscott , customer did it . So I don't know yet. Do you think electric eye could only be problem at idle. If so I have new one on shelve

 

[flyingscott]

I.would.do.a.compression test and spark test first. Then I would.look at the optical sensor just to.make sure.it is.in good shape. Then I would look at the carbs and make.sure they are adjusted correctly.

 

[Mikey N.C.]

Yes synchronized, customer took to a shop after carb. rebuild to sync. And that can be out especially if cam roller is missing . But keep in mind 21 hrs. 2001 yr. Garage kept he pulled carbs. Hole shot is quick and 58-60 mph.as as fast as you want, motor is on a 2001 Sprint 290 DC 18 ft. I thank. I couldn't get it to chime walk, but I was in a head wind maybe 3 -5 mph.

 

[Faztbullet]

Check sync and link on top of flywheel cover and adjust carbs per manual...in water, in gear, untethered

 

[Mikey N.C.]

You are talking about. Trigger screw? That u can't get to unless cover is removed, or unless u put in wot .

 

[Mikey N.C.]

I'll look tomorrow. Does that oil line , fuel line connection on port side to motor have issues

 

[flyingscott]

You cant run that motor with the flywheel cover off. The adjustments are on the cover.

 

[Faztbullet]

The adjustments are on top of cover as I posted and there is no timing screw

 

[Mikey N.C.]

Ok that's with cover off .i don't have tool to adjust timing. That takes a special timing tool rite ? I know I can't run motor with cover off .
Thanks for replies, but. I'm not understanding , how idle can be timing. Please explain.
it's a osi shouldn't, timing be correct at all times. ?

 

[Mikey N.C.]

Or at idle osi loses signals? Could it be low battery just a thought

 

[Faztbullet]

Yes you can run with cover off but not in bright sunlight but be careful of spinning encoder wheel. You can advance or retard idle timing on adjustable slide lever.

 

[flyingscott]

I.think you are mistaking the motor hood with the flywheel cover. Omc had been setting the idle with timing for years. Maybe you need to get the manual for that specific motor. It is an OIS ignition not osi.

 

[Mikey N.C.]

Correct it's OIS. Today ran on muffs after motor was warmed up . idling at 1000 rpms , idle would drop to 900,800,700,600 then sneeze and cut off. Read that factory idle air jet is 4 turns out after seated. So I checked settings. Top to bottom, starboard side was 4 turns out , 5 1/2 out and 4 1/2 out. Port side 6 turns out, 5 out and 6 1/2 out. I seated all and backed out 4 turns. Cranked motor and let run for 30 mins. it never dropped below 1000 rpms. So lake test is next. Thanks for all replies.

 

[oldboat1]

Back pressure will probably push rpm down about 300, so about where it should idle. You likely will need to tweak the jets a bit in the lake before turning it over to your customer. (Probably wouldn't be a bad idea to jot down the settings too, so when the user messes it up resetting will be easier.)