83 ranger/johnson gt150 lake test NOT GOOD

[motodave]

Took the boat to the lake yesterday after carb rebuild, didn't go so well and I could use some advice on a plan of attack. The rundown:
I was very careful rebuilding the carbs, replaced all needles, seats, seals, gaskets, floats, (OEM) blew out all passages with compressed air, set the float height to level with the carb body. I also pulled fuel from WHAT I THOUGHT was the bottom of BOTH fuel tanks, looked and smelled fine, and I did add 5 gallons to the left tank, 50:1 ratio. So I put it in the lake, warmed up the motor and idled out, seemed to idle a little better but still a little rough. I open the throttle, and there is a dead spot right around 1500-2000 rpm, motor would die most of the time even moving throttle very slowly. I must have missed something in rebuild? Anyone know offhand what jets the carbs use at that rpm range? In neutral the motor would rev out fine, and I was able to get it up on plane by getting rpms up a little and quickly shifting into gear, seeming to 'go past' the dead spot before it had a chance to die. So after cruising around a while (runs good up top, would push 60mph) I decided to switch fuel tanks, motor died. When restarting it would only run a few seconds. Pulled the outside fuel line, pumped the primer and VERY rotten gas comes out. Not another boat on the lake, so I switched the fuel tanks back, pumped till I saw clean fuel, drained the carb bowls and was eventually able to get it started, hauled butt back to the trailer. My question is obviously what did I miss, but also could I have done damage to the motor? Pretty discouraged at this point, any advice? Questions? Slaps? Jokes? All is welcome

 

[Tnstratofam]

I had a similar problem on my Chrysler outboard. It had been sitting for a long time, and had bad gas in the fuel tank. I ended up doing several things. Replaced all fuel lines including the lines between my three carbs. Replaced the primer bulb. Cleaned the fuel tanks ( mine are two 6 gallon portables so it was pretty easy). Pulled all three carbs completely apart, and made sure all jets and passages were clean as a whistle. Replaced the fuel pump. Put in new spark plugs. And checked my timing. I also replaced the impeller in the lower unit ( a must for an unknown engine). Cleaning the carbs was the hardest part. It takes patience to ensure you don't miss a set of jets. I had to remove everything to ensure it was clean. I also installed a clear inline fuel filter between the primer bulb and the engine to ensure the gas was #1 getting through, #2 was clean. Did all that and she purrs like a kitten now. I really can't stress enough you must take your time, and make sure everything is cleaned well. You'll be chasing your problem for days if you don't get the basics out if the way. Good luck.

 

[emdsapmgr]

Best to just pitch any old fuel in both tanks and start with fresh. Keep in mind that water accumulates at the bottom of the tank, so be sure you siphon all of it out before adding new. (Possible the fuel in that one tank suffered from fuel phase separation.) That should clear up at least part of your problem. When you said you cleaned the carbs, that must include the following: remove all the jets (with a special tool), visually inspect them for debris, dried fuel gelatin or restrictions. Also, you can't blow dried fuel out of carb passages. You need to dissolve it with a carb cleaner. Squirt a carb cleaner thru each carb passage, each jet and verify the spray out of the other end of the orfice on all carb openings. The mid range bog may well be related to a restriction in the mid jets, found inside the carb bowls. Top side. Again, remove them verify they are clear and clean the passages with carb cleaner. (Like a Gumout product.) Once you get past our mid-range bog and onto the main jets, the engine seems to run ok. That's good-means the mains are still flowing fuel. You can look at the factory exploded parts diagrams for your engine at this factory website: epc.brp.com. You can check out the jet sizes. Stay with the recommended factory jets. Keep in mind that you have a 150GT. Different than a straight 150. Look for the parts diagrams for the 150S model only. (puts out about 165 hp at the crank.)

 

[motodave]

Thanks for your response guys, emdsapmgr - I did not remove the the jets in the bowl, but I did spray carb cleaner through them before air and saw light passing through, however I know the only sure way is to remove them, so I will do so on this second round. Hopefully that is the problem. Thanks for the website and noting there is a difference in models I wouldn't have caught that, ordered the parts through marineengine.com using the model number so Im assuming they were the correct parts. I would like to remove the fuel tanks to be sure they are 100% clean, but it looks like a booger so Ill probly siphon and siphon some more. Thanks again!

 

[racerone]

How long have you owned the motor ?------ Did it run properly before the carburetor work ?----Has a compression test been done ?

 

[motodave]

racerone - I just bought this boat several weeks ago, it ran before the carb work but did not want to idle while in gear, would idle and rev fine in neutral. The carbs were leaking, bad float needle and gaskets, and missing gaskets. Probly a huge shocker but the guy I bought it from wasn't completely honest with me. I also made the mistake of buying without lake testing, as the only lake within hours was shutdown and it was about 25 degrees outside. He told me he had it serviced a few months ago and compression was 80 on all cylinders, written on them with a sharpie. I am waiting on a buddies compression gauge and will check it and post it. On that note, is there a sticky somewhere on the proper steps for compression test? Cranking the motor with no fuel in it makes me nervous. It runs awfully strong once it gets on the main jets so I sure hope Im not screwed!

 

[racerone]

There seems to be a lot of confusion about lubrication on 2 stroke engines !!!!!!-----There is no problem doing a compression test on your motor .------The oil that is inside the motor and coating all the parts just does not disappear when you turn the key !!