Logo
FULL SITE MENU

2002 Johnson 115 Surge/Bog/Smoke issues

D

d.glennon

New member
Hi All,

I have a 2002 Johnson 115 that I am having issues with. The motor will surge at high RPMs while underway and eventually bog down. When starting it up it is rough and often stalls when shifting it into gear. In addition, the motor smokes like a chimney and dumps far too much raw fuel out of the exhaust.

So far what I have done on the motor is the following:
Compression check (all four cylinders good and even), checked for spark, brand new 3/8’’ fuel line, new ball, new racor 30gph fuel water separator, new fuel pickup from original polyurethane tank, fresh gas. A few months back a mechanic friend of ours replaced the VRO fuel pump, it was not running prior to that for a few months and this was deemed to be the culprit. Now with everything from the fuel pickup to the VRO Fuel pump being brand new, it is still far from running properly and I have thrown $1500 in parts alone into it.

In addition to these parts, I removed the intake manifold to spray out the screens and check valves, disassembled the carbs and sprayed them with no apparent issues. I am at a crossroads because the outboard mechanic I took it to for the compression and spark check tells me it is most likely a bad fuel pump hence the excess smoke and the engine acting like it is either starving for fuel at high speeds or running way too rich at idol. I was planning on either A) disassembling the VRO as much as possible to check for any issues (cheapest 1sr step) B) Purchase the carb rebuild kits, replace all gaskets as well as the check vales within the intake manifolds which would amount to about $350 in parts, or C) which would be to replace the VRO Pump for the second time, $400+++. (too much time has lapsed to try to get a new one from the original replacement vendor).

All mechanics and forums say to run the boat off an external tank however as mentioned above, everything in the fuel system is new so I can seem to make sense of spending $50 on a 5 gal tank when there should not be any issues between the tank and the fuel pump.

Any suggestions are appreciated!
58857.gif
 
Thank you,
However when I spoke the mechanic who ran the diagnostic on the motor, he said the the compressions was good, carbs were good and the cylinders were firing fine when he ran it at his shop. His suspicion was a bad fuel pump which would explain the excessive smoke too.
 
Answer questions.--------What are the compression values ?-------------Does spark jump a gap of 3/8" or more on each lead.------------How do you think a VRO pump can make the motor smoke too much ?----Does the primer bulb go hard when you operate it, yes or no ?
 
Mechanic said all four cylinders were around 130, not sure about the specific spark but the mechanic said all were tested and they were all "good."

Primer ball is brand new, manually you can pump it hard as a rock but once the motor burns that gas the ball is empty, motor only runs at high RPMs when I have someone pump that ball as I open it up.

As far as the VRO, the motor is not getting fuel at high RPMs, bogs down and stalls at low RPMs indicating a fuel delivery issue, on top of that the motor is running so rich that when at the launch, the parking lot will fill with smoke, it’s always been a Smokey engine I believe these Johnsons are notorious for that but this is excessive and clearly inefficient.
 
Find out why the new VRO is not supplying the fuel !!-------Perhaps test run with a " known to be good " hose and portable tank.-----------Have you checked the vapor seperator pump ?____Red lever on the primer valve in the correct position ?
 
Last edited:
Bogging,excessive smoke,etc are symptoms of failing VRO or air leak making VRO cycle rapidly. These are bad about the air motor failing.
 
But this is a brand new VRO pump according to post # 1 here.
Click to expand...
That dont mean much these days..rebuilt a 200hp several years ago and had new VRO installed, 6 hrs later and 3 week of back and forth with factory and independent testing company got a new powerhead as VRO pumps straight gas to carbs. Back to original PO problem check for air leak or cracked VRO housing.
 
I've been having this same problem with my 98 Johnson 150. It was smoking a lot & used way too much oil. I put a new VRO in, and no more smoking or using too much oil. Shop told me the VRO was ok, but it appears to have been faulty. I'm still experiencing stalling when I give it throttle a little at a time, but nothing like it was. I think the issue now is clogged idle pocket or carb or a small air leak around one of the carb gaskets or throttle body gaskets.
 
Hi All,

Thank you for the responses. Unfortunately this project fell on the back burner for the last couple weeks but I'm just now getting back into it. Contacted boats.net, where my handyman bought the VRO and they will not replace the pump. Lots of resources including the mechanic I had check the compression and spark say to run the boat off of an external tank with premix. Does anyone have a good link to YouTube or another forum that explains the proper way to do this. I figured its worth a few hours of my time before spending another $450 on a new VRO? Also customer service from boats.net claims the VRO can be rebuilt but I have been told otherwise so I am hesitant to put any time or money into investigating, any thoughts ?

Thanks!
 
Back
Top