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Running rough

jshane37

Regular Contributor
"1997 Johnson 200hp, 227 hours

"1997 Johnson 200hp, 227 hours.
Recently replaced fuel pump, primer solenoid and vacuum switch. Boat will run "ok" with some misses and backfires with red switch on primer solenoid in the up/prime position. Will run about the same with it in the run position but will eventually shut down as if starved for fuel. Primer bulb is not flat and seems to prime line ok. Engine will fire if I keep priming bulb pumped prior to starting. Have not tried pumping it to see if the engine will contine to run while doing so. This test run was not done under load of water and was done on the hard with muffs.
Anyone?"
 
why did you replace all those

why did you replace all those components?

did it do this before?....if not i would say you may have gotten something wrong.

if it did i would say your carbs need a good cleaning and rebuild.

im not familiar with your eng but im pretty sure that red lever is manual choke....if everything is working right you should be able to prime it with the key.
 
"Components replaced due to ro

"Components replaced due to rough running and shut down conditions at the end of last season, as suggested.
Prior to this condition, did not inspect the carbs. Would prime by key and run great for the duration."
 
this looks to me to be a long

this looks to me to be a long one!
Let us from the beginning either keep the boat in water (launched) or get a barrel and have the lower unit submerged in water to normal depth. Throw away the muffs!!!!!!!!!!!!!!!!!!!
1: Does the engine start and run normally?
(Quick start engages and quits when engine reaches temp).
2: Does the engine keep on running even when shifting in and out of gear?
 
"10-4 on chucking the muffs!!

"10-4 on chucking the muffs!!
Engine will start and run fine with the primer lever in the up position. I say fine, it misses and backfires but will stay running. Will seem to starve and run out of fuel in run position.
Engine will keep running while in gear but has the same results with primer lever in up and down position.
Tricky one eh?"
 
"Then on to next steps. A heat

"Then on to next steps. A heat gun would have been the best, next best is Your hands,
Putting Your hands on top of the block/cyl's, temp should be even on both sides and barely to touch.
If smelling bacon -too hot.

Then pull all plugs and if possible take a pic and post, or up-load them somewhere else and post the link.

When You say: shut down like staved for fuel.
Do You mean just slowly dies, or does the engine sneeze and stop?"
 
Take pictures of the plugs?
I


Take pictures of the plugs?
I get a sneeze and a stop. Will stay running (though quite rough with that primer lever in the up position) Sneeze/backfire and stop with lever down in run position.
Will check the temps shortly.
 
"What about the quick start?

"What about the quick start?
At start (cold) engine will run at about 1100 rpm, then drop as temp goes up.
Is quick start working or not?"
 
"The enclosed picks shows Your

"The enclosed picks shows Your carbs.
Note adjustment screws #12 which is for idle mix.
Leave Your primer solenoid in normal 'run' position and turn ALL screws 1 turn out. Does it make any change in how the engine runs?

I'll be off for the night, it is almost 23.00 where I am. Be back tomorrow to collect the latest updates.
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"
 
Very well thanks Morten.
Yes


Very well thanks Morten.
Yes David there is a fuel/water separator filter. I drained it prior to attempting start up this year and did not find any water in the glass jar that I drained it into. Had a bit of a foul odor but nothing overwhelming.
 
foul odor??

do you run fuel


foul odor??

do you run fuel stabilizer?

how long does your boat sit in between uses?

most of your symptoms point to the carbs imo..wehn you said rough running conditons and shut down last season: was it runnin rough all the time or jsut at idle?
 
I put a stabilizer in during t

I put a stabilizer in during the off season. Was running great last season until my last trip out where it lost power and died in the water. Managed to get it started and nurse it back to the dock. Ran like it was missing the whole time while putting back in. Has sat on land since october of last year until yesterday when I replaced the above mentioned parts at the recommendation of some of the great people on this site.
 
"why don’t you replace f/w sep

"why don’t you replace f/w separator filter just to make sure there is no restrictions, since you installed a new pump, I went thru a lot of the same issues you are having and my issues started to solve as I tossed my glass fuel filter as it was very restrictive and stopped using small portable tanks, I use a regular filter now along with a f/w separator, no water in your bowl does not mean the filter is not clogged so give that a shot, also if you have quick disconnects that could be part of the problem and make sure you use 3/8 hose too."
 
"Sounds like a plan Nicknack2.

"Sounds like a plan Nicknack2. Will give that a try since I am/have already replaced everything else!!! I have a built in tank, and a plastic in-line filter. FYI"
 
"10-4 give it a shot, it took

"10-4 give it a shot, it took me about 4 months to get to solve my issues and still fine tuning, I also ended up taking my stationary tank off and gave it a good "wash" after the wash I think I still pulled about a pound of dirt out of it....."
 
"Ok after replacing the fuel p

"Ok after replacing the fuel pump, the vacuum switch, primer solenoid, plugs, fuel water separator, spring clamps around fuel lines, fuel bulb, and draing the gas tank and starting from scratch with fresh fuel I seem to be running ok. Have not tried it in the water yet or under load, but its a start. Thanks to all for the help.
Anyone have any ideas on how to help with a built in plastic fuel tank that seems to be buckled in? Throws off my actual fuel reading!!"
 
"you might be having venting i

"you might be having venting issues that is why your tank is buckling, that in fact might be the answer to all your issues..."
 
"Oddly enough nicknack2 after

"Oddly enough nicknack2 after pulling and reading many threads in the archives, that was one of the first things I checked. I pulled the vent hose from the tank itself and followed it out the port side of the boat. Checked completely clear. It sags about an inch exactly where my rod goes into the tank, thus throwing off my fuel reading. Was not sure if anyone knew of any fixes for that. Oh and it was like that when I bought the boat prior to my "running rough" experience."
 
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