03 JOHNSON 90

[JLH 34]

Hi, I have an 03johnson 90 hp.I bought it 3 months ago and since new it misses between idle and 1600 rpm.I have taken it in several times and they have fixed thermostats, changed plugs and the last time adjusted carbs,set timing and adjusted linkages but still the same problem.If you take off slow or idle around the lake it shakes and stumbles also wen you run the engine and come to a stop it likes to idle around 1300 rpm for a few seconds.Before the carbs were adjusted the plugs would be wet when i pulled them out and now they come out dry with a light brown appearance.Any help would be greatly appreciated. Thanks in advance,Jeff

 

[clanton]

Re: 03 JOHNSON 90

I would pull the carbs, clean float needle/seat, check carb for trash, check float settings, all gaskets, check jet size, intake gasket, do a link and sync, check idle timing, full advance timing. Check vapor seperator. Ignition system system running test, as outlined in service manual. Fuel system inspection, must hold pressure and vacuum. Check for coil arcing to metal plate between coil and power pack. Did you buy motor new out of box? I have seen some late model 02, mabe 03, with trash in the fuel system from factory, and the engine filter was clean.

 

[JLH 34]

Re: 03 JOHNSON 90

Clanton,<br /> <br /> Yes i bought the motor new it was a boat and motor package.<br /> I was messing with it tonight and found the balance tube hose was completely kinked around carb going into air silencer.I re-routed and shortened the hose.Could this possibly cause my missing problem?<br /> thanks Jeff

 

[clanton]

Re: 03 JOHNSON 90

The high idle for a few seconds is because it is running lean. I would check the top strb carb for trash on float needle, and bowl. Any trash (metal shavings) all 4 carbs and fuel system all the way to pickup tube should be cleaned and checked. If the hose is the one that goes to the vapor seperater the kink will cause hard starting.

 

[JLH 34]

Re: 03 JOHNSON 90

Ok i cleaned all 4 carbs and replaced gaskets.Seems to be a little better.I pulled plugs and they were pretty wet.The needle valves were out between 4 and 4.5 turns(carbs were adjusted by mechanic at marina). My manual doesnt give me factory settings for the needle valves just how to fine tune.Can you give me factory settings?4-4.5 seems a lot to me.<br /> thanks

 

[ob]

Re: 03 JOHNSON 90

3 to 3 1/2 seems closer to ballpark on the idle mix screws.However there is no exact set in stone as each engine and particular backpressure application will vary.Just for grins insure with a visual that the carb linkage roller is aligned on center and 'just touching'the scribe line of the fiber throttle cam when controls are in neutral.<br /><br />Also I'm assuming the engine is already mounted to its optimal height setting.I see lots of engines that are mounted too low which causes excessive exhaust back pressure and poor low speed performance.

 

[JLH 34]

Re: 03 JOHNSON 90

ok this thing is still missing.So i took it back where i bought it and told them to fix it right or give me a new engine.Is there a lemmon law on outboard engines like cars?Ive been back to this place so many times for various things in the last 4 months and this is the fourth time for the missing issue.The first time i took it back they made me spend $22 for spark plugs and it was only run for 30 minutes from being new.A week after buying this thing the gear lube leaked all over my garage floor(no gasket on drain plug). sorry for going but this is getting crazy.

 

[ob]

Re: 03 JOHNSON 90

I agree.A new engine is just that.They need to make it run like a new engine or replace the unit.I'm confident that you will get some satisfaction one way or another.

 

[JLH 34]

Re: 03 JOHNSON 90

Ok 3 more trips to dealer and same problem?They replaced vro and rebuilt carbs.They tell me it runs perfect in their tank.So i take it back today and they dunk it in the tank and it runs perfect.I tell them to run to the lake with me so they sent a non mechanic with me.The engine was back to missing(studderind?)from idle to 1600 rpm.Any idea why it runs flawlessly in the tank and bad in the water? thanks

 

[DJ]

Re: 03 JOHNSON 90

How low does the engine sit in the water at those speeds?

 

[JLH 34]

Re: 03 JOHNSON 90

The engine is in the middle bolt hole.The cavitation plate is probably 2-3" below bottom of boat.I suggested raising the engine to the mechanic and he said it would only affect idle.When it was in the tank the engine was much higher.

 

[DJ]

Re: 03 JOHNSON 90

There you go.<br /><br />I am assuming that this engine is on a planing type boat. If so, the cav. plate sitting that low will NEVER allow the engine to perform up to its potential. What is your wide open throttle RPM?<br /><br />I think the engine is having trouble breathing and is severely lugging.

 

[JLH 34]

Re: 03 JOHNSON 90

This engine is mounted on a smoker craft 162 millentia with a max hp of 90.this engine seems kinda heavy for the boat and the back sits pretty low.

 

[JLH 34]

Re: 03 JOHNSON 90

5500 rpm

 

[DJ]

Re: 03 JOHNSON 90

The RPM is OK. I still think it is sitting far too low. <br /><br />It certainly will not hurt to raise it. Make the adjustments one hole at a time and record your top rpm at each setting. You can go 6000 without any harm to that engine.

 

[JLH 34]

Re: 03 JOHNSON 90

ok its at the dealer now and im trying to call them.There is only 1 more hole that it can be raised. Thanks for the help

 

[DJ]

Re: 03 JOHNSON 90

This seems like a real mis match.