1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

[WarOzz]

Hi all,

I have a 1968 Evinrude Sportsman 155 with the 225 V6 and the Rochester 2G carb. I just rebuilt the carburetor and replaced the float. I upgraded the points ignition to an HEI unit out of a 1975 Buick Skylark. Thing fires right up, idles and times well. Main symptoms are... as it warms up I get lots of blue smoke, stutters on acceleration, plugs fowl out (charcoal dust on them) , hard to restart if it dies.

I have played with the timing from 4 degrees to 12 degrees, I can get it to idle pretty smooth. Like I said as the boat warms up it starts running rougher then eventually will stutter on acceleration and then just die at idle and is hard to restart. I thought maybe I had it running to rich so I backed out the mixture screws another 3/4 turn, didn't seem to change anything.

Any help or ideas would be helpful!

 

[Maclin]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

Make sure the choke is opening.

 

[WarOzz]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

To be honest I don't even have the choke hooked up right now, I added an electric and have not run the the wire yet, so yea the choke is open.

 

[cr2k]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

Um the choke should stay closed without the wire attached.
The wire runs a heater that will OPEN the choke after a short time.

Blue smoke is oil smoke. You may have broken or worn rings, or valve guides.

 

[daydreamer1252]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

Something for you to look into...the Buick V6 in your OMC application was a 90 degree fire V6 it was a V8 with 2 cylinders chopped off. They kept the crank as it was a V8 because it was far cheaper than re-engineering for an even firing 60 degree crank. When Buick bought the engine and tooling back from Kaiser-Jeep-American Motors they did the required re-engineering and put a "proper" 60 degree crank in the motor. I don't know exactly which year that new crank was first used.

If you have a later model EVEN fire (60 degree) distributor in an engine with a 90 degree crank, you will not have the spark on the secondary cylinders (all except #1) happening at the right time. This will cause all kinds of poor running symptoms.

Just something to check.

 

[Maclin]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

To be honest I don't even have the choke hooked up right now, I added an electric and have not run the the wire yet, so yea the choke is open.

As cr2k mentioned, this description is of a choke that may never open! The electric part is what OPENS the choke. You will need to unhook the choke linkage and wire the choke plate open, or just get the wire hooked to a 12v ignition source and make sure the other is grounded.

 

[ziggy]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

i'm no pro on your engine, but since this is open for anyone to comment.....

generally speaking...

blue smoke i think means it's burning oil. black smoke means it's to rich from the carb. white smoke means it's trying to burn water.

ya should use marine rated peripherals on your engine. a auto distributor probably don't meet the criteria for spark suppression. if ya get a fuel leak, well, ya get the idea. boom.

ya need to set the timing with a timing light to whatever is specified by the mfg. for your system.

i think i'd put the points back in it. dwell and time it to specs. that way, if it runs poorly, at least ya might be able to assume it's the rebuilt carb thats causing it. right now, your perhaps battling two issues and don't even know it.

ya might take a compression reading. http://www.boatfix.com/merc/Bullet/97/97_25.pdf from adults only sticky.

backing out the mix screws richens the idle mix. more fuel.

 

[WarOzz]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

First off thanks for all your ideas! You guys got me thinking and I am now heading back to the drawing board and solving one issue at a time.

I am very familiar with the AMC 225 Buick 231 90 degree odd fire engines, this isn't my first dance but it's for sure kicking my but. I have had a 72 Vega (yes i said vega) with a 75 odd fire 231 for about 23 years. I purchased the fixer upper boat because it had the original buick - sold to amc 225 motor. I picked this boat up for just a couple hundred bucks with the intention of being able to use a few of my old buick parts I have accumulated over the years and have some fun. I know engines but nothing about boats lol. Took me a all last summer just to get the gel coat shining again, interior redone and rewired the entire boat. This year when I went to fire it up I had obvious carb float problems so I rebuilt the carb and decided while I am at it to do the HEI that I had already researched. Bad idea!

As of today I am installing the old distributor back in and will use it to dial in the carb before trying HEI again. I have a feeling it might be time to toss the old carb and go with a re-manufactured but I refuse to give up. I will post progress here and appreciate any ideas/suggestions anybody might have.

Thanks!
Ed

 

[WarOzz]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

Hi everyone,

I thought I should give a little update as to my failures and success so far.

After posting last time I pulled the HEI and carb off and started from scratch. Reset float height, was off a little set mixture screws to 1 1/4 turns out (this on the advice of several local mechanics at my altitude). Then I hooked up a nice easy to operate manual choke. With the carb issues now fixed and the old points ignition system back in the boat is good. Still a little rough at idle and hard to start when cold. So now back my HEI upgrade I go! I decide to go from total scratch, bring the engine to TDC manually then install distributor. Come to find out I was one tooth off from were I had it installed before. I went ahead at this time and manually timed it to 12 degrees BTDC, again this on advice from local mechanics, ran my 12 volt and tach to distributor and fired it up. wow!

I gained immediate start up without any hesitation, no more stalling when cold! At idle I picked up almost 200 rpm so I was able to back the idle screw down a bit on the carb. At WOT she just purrs. The best part is the mileage , I used to run all day fishing, water skiing, pulling the tube etc on 12 to 13 gallons of gas, this last same type of trip to the same lake was right at 7.2 gallons for a full day of fun!

Although I had a few problems getting there I would suggest an ignition upgrade to anyone running one of these old v6's, for the cost it pays for itself in gas the first season. Of course rebuilding the carb didn't hurt either

Thanks to everyone who tried to help!

Ed

 

[Engineer719]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

I have a 68 Sportsman as well. What make.model HEI did you use?

 

[Don S]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

Please don't reply to old threads, the original poster hasn't even been back to the forums since 09.

 

[WarOzz]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

wow I can't believe this old thread of mine is alive someplace still. I actually sold the boat in 2011 to finance a move to the Oregon Coast. But I can still answer this simple question.

I have a 68 Sportsman as well. What make.model HEI did you use?

HEI unit was from a 1975 Buick Skylark v6 231 naturally aspirated 2 door automatic... need to know more?

I had this distributor for years from a car I bought for parts. I did go thru it and put in a shim kit, and an advance kit along with a new module. Any pre 1979 odd fire Buick v6 231 distributor should work fine for you. The key here is "odd fire", which is what your boat engine is.. newer 231's.. 1978 and later I believe were even fire and the distributor Is different.

 

[Engineer719]

Re: 1968 Sportsman 155 Help Plz! Rebuilt carb still not running right!

You are awesome.thank you! Im gonna stay stock for now, but maybe later I can upgrade for performance...thank you for replying.