150 Oceanrunner Johnson Vibration worries

[pappygt]

Just boat a 96 Welcraft Coastal 264 with twin '96 - Johnson Oceanrunner 150's which sat for two years and is now back in water. Test ride was - put new batteries in and turn key... have had out 4 times and about 45-60 mins engine time. Gas is 2 years old as is oil and impellors but it runs out great at speed and cranks up ok... maybe a little hard idleing but accetable....

2 questions - burn out gas fully (down to 3/4 now) then add new or - add new as you go? Some say ad is better, some say the 2 year old gas has no ethanol - dont add new gas to old.... so I'm stuck

2nd question - when I back down from running at speed and somewhat while ldleing out of marina, I notice a shudder from the engines.... I think it's the port only but haven't truly tried to run one thn the other to verify but there's a shudder.... it feels that way - even though I'm new to boat - I just feel a shudder... props are VGC - no nicks, nothing bent, I thinkk they ar estainless that were painted over... but they seem fine. Motors and boat while it sat - is still in VGC... motors will idle ok.... not smoke too much.... but I feel a shudder I'm pretty sure.... but 4 trips and no issues so far till I read about guys haveing blts sheared off of cranks or bell housing or something... now I don't know if I'm being pranoid or I should do some more checking.... help.

 

[Fl_Richard]

Re: 150 Oceanrunner Johnson Vibration worries

My twins sometimes at idle (1995 Coastal 238 w/ 150's) will shutter. I think it's more of a harmonic imbalance caused by the props spinning slowly but at different speeds. usually changing the RPM of either one slightly will be enought to make it stop.

Most would say pump out the old gas. I personally would fill it up with fresh stuff and use the entire tank in a weekend or two.

BUT First - Change the fuel filters and ensure you have two additional spares on board. - If not needed immediately next year you can use them.

AND - rebuild all 12 carbs, even if it looks like they dont need it. Remember fuel is the lubrication. If one in 6 carbs is slightly plugged that piston gets less oil than it requires. This is good insurance especially since it's been sitting awhile. You can do it yourself (1- afternoon and $120 per engine) and you will know they are good.

 

[pappygt]

Re: 150 Oceanrunner Johnson Vibration worries

Thanks for the reply - pump out old gas?... well - I could put on trailer and fill my van... don't want to throw away 80 or more gallons of fuel.,... do you think a v-6 Town-n-country van would burn thru gas with less to worry? I could burn thru gas easy that way... but I'm not out long enought to burn that kind of fuel up on the water - man - to be forced to run your boat - what a predicament... maybe I'll change my mind on that...

Rebuild the 12 carbs - I've goty a carb phobia from when I tried to mess with a quadra-jet on my ford and springs and stuff just started popping out and I went out ands bought a rebuilt Holly... since then I was afarid to mess with them.... but I mess with pc's all the time and am fine with other mechanical stuff so maybe I just need to try or hear it's not that hard....

Same wqith water pumps - the mechanic wants $400 per engine? to replace?... Christ... says he has to test shifting, etc first, get in shop -... all I care about is finding out how to disconnect the shift lever - something about being behind the 6 carbs? any input there? Otherwise you unbolts 6 or 5 ... I know one is hidden by the zinc.... I've done a few on 70 & 85 horse... my only issues there were a stripped bolt which I'm hoping wont be the case on these.... and which way to twist the impellor when putting it into the cup. I know you shoul dreplace the base plate and top plate if even slightly scored... thanks again and let me know about those carbs... how easy are they?

 

[jonesg]

Re: 150 Oceanrunner Johnson Vibration worries

Get the factory service manual, you can do all that work in a long afternoon yourself. Save yourself $1000 easy.

www.outboardbooks.com

I ran 40 gals of old fuel thru my truck, add some dry gas to perk it up.
Mine had water in it , i let it settle in buckets then syphoned the water out.