2002 Johnson 175 (60° BRP Looper) run great then dies

RamboChambo

RamboChambo

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Joined
Apr 4, 2019
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6
I recently purchased a bass boat with the aforementioned motor and have encountered an issue that I'm having trouble diagnosing. When I test drove the boat, it ran great in all rpm ranges before one of the carbs started leaking fuel. It ran like crap and would idle but as soon as I touch the gas it died. Seller said he would have it fixed at no cost to me. He said mechanic had just rebuilt all the carbs and may have missed something. (Mechanic also previously did plugs, wires, checked timing and synced carbs as well)
The following weekend I took the boat out and it was running great again for about 20 minutes, i came off plane to let a boat go by and after idling for a minute or two, i noticed an audible miss. Soon as i touched the gas, it would die. Primer ball seemed a little spongy but squeezing it did not help it. It idled back to the ramp without cutting out. Has all new gas (premixed 50:1)

I replaced the primer ball and a fuel line section that was kind of "rigged", checked and cleaned the fuel filter (was pretty dirty), checked fuel/water separator and replaced (no water found in jar after 24hrs but figured i might as well), did a vaccuum test on carbs (no issue), rechecked compression (102-106 across the board), ran Powertune through carbs and changed plugs.
Test drove it last night and it ran like a scalded dog and purred like a cougar til i came off plane after 20 mins or so. Idled and started missing again. Soon as i touched the gas it would die in neutral and wouldnt idle in gear (starts right up). Ball was tight. No alarms or warning lights on the New Systems Check gauge. Did not seem to be overheating. Pulled plugs (all look great, no fouling or signs of running lean. Warmed motor on hose and did spark check. All looked great. No signs of arcing in the dark with cover off either. Im stumped...
 
oldboat1

oldboat1

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Apr 3, 2002
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9,612
ran like a scalded dog, purred like a cougar, then suddenly stalled like a hillbilly brain on ‘roids. Shops usually use their own gas for control purposes. Guessing — If you have signs of contamination on a first run, it’s likely contaminated gas in the boat tank. Carbs will need to be cleaned again (might be on your nickel or the prior owner’s.)
 
RamboChambo

RamboChambo

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Apr 4, 2019
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I'm not concerned with the nickel part 😉 Was finally able to contact the mechanic who worked on the boat previously. Previous owner accidentally gave me the wrong number, one digit off. We spoke in length of the aforementioned issues and he will be out tomorrow to go thru it and diagnose it for free. He also stated there will be no charge if it was something he previously worked on. Starting troubleshooting with the OIS, then working his way to the carbs. Guess we'll see
 
RamboChambo

RamboChambo

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weaverunner said:
This all sounds too familiar...I spent all last year chasing what I thought was a fuel-related issue on my 60* v4 but it ended up being my timing was out of spec. Before you start replacing parts. check that your timing arm/rollers are in the proper position. Instructions in the link below.

http://www.bbcboards.net/showthread.php?t=11790
Click to expand...

Thanks.I ended up calling a mechanic to look at it. Discovered an overheating issue. Thermostats were clogged. Replaced both and impeller. Ran great in the tank at the house. Took it out and it seems to be something to do with the linkage. Put it in the water and it started acting up again. He manually advanced the throttle and it cleared up and ran like it should. He's going to take linkage apart next week and make sure nothing is cracked or damaged then do a sync n link and go from there.
 
J

JerEazy

Petty Officer 1st Class
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Jul 26, 2017
Messages
234
Curious - the link and sync should have been done after the carb rebuild.


If i if I had to guess I would say a float issue in the carbs. Using the gas on plane and at speed. Pull back and the bowls fill again but the fuel isn’t being used and it floods.
 
RamboChambo

RamboChambo

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Joined
Apr 4, 2019
Messages
6
So... My buddy is an OMC tech of 15yrs and finally had time to go through it. It appears that the carbs were never done amd were nasty. Two of the o rings were pinched. Still had the factory gaskets on it etc. Nothing that was said to be "new or looked over" had been done. My buddy did a thorough cleaning and complete rebuild on the carbs and tuned them to the correct tolerances. We drained the tank, replaced the sending unit (original, and had almost completely disintegrated into the tank), replaced all fuel lines and filters. He re-synced everything and adjusted the timing. Runs like a raped ape now. The other two "mechanics" had no idea what they were doing lol. So after 2 months and headache after headache, she's finally right. Never purchasing a boat with out it being completely gone through by a certified mechanic. Lesson learned.
 
C

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
28,563
Did you need to replace the plastic carb bowls? They have a tendency to warp and leak. The motor can still run OK, with warped bowls.
 
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