Nissan 9.8a2 running rich on top cylinder?

[clintbeastwood]

not sure whats up with this one. tight intake valve on bottom cylinder making the top cylinder suck all the fuel?

 

[clintbeastwood]

Re: Nissan 9.8a2 running rich on top cylinder?

nope intake valves right on @.14mm

 

[Chad N]

Re: Nissan 9.8a2 running rich on top cylinder?

If its carburated check needle valves and float height. If injected check for carbon build up or anything restricing intake path. Also check injectors to be clean and in proper condition.

 

[clintbeastwood]

Re: Nissan 9.8a2 running rich on top cylinder?

2004 carb. its super clean soaked in cleaner , i was think air passageway in carb stoped up i have that happen on a motorcycles, but its clean float heights right, bottom plug looks lean now? both plugs were very sooty yesterday?

 

[clintbeastwood]

Re: Nissan 9.8a2 running rich on top cylinder?

This engine has one carb for two cylinders.

 

[TOHATSU GURU]

Re: Nissan 9.8a2 running rich on top cylinder?

Get a service manual, open to ignition troubleshooting and run the tests. Think in terms of why one cylinder runs well and one sucks when they both feed off the same carb. This sounds more like an ignition problem, but on an 8 year old engine it could be anything from a bad spark plug to a stuck ring.

 

[clintbeastwood]

Re: Nissan 9.8a2 running rich on top cylinder?

Yeah Tohatsu Guru thats what I was thinking the electrical part? I dont have a manual and know I need one but it has a single simese coil with a wasted ex. spark and it jumps a 6mm gap on my tester with a big fat blue spark? Timings good , Id take it to a dealer but its 3 in the state that I can find and unless they have seen this before I their going to do the same things i have done.

 

[TOHATSU GURU]

Re: Nissan 9.8a2 running rich on top cylinder?

There is no substitute for the factory service manual. The test procedure for the ignition system is really involved with multiple values. Do yourself a huge favor, stop for now, order a manual from someone and just wait till it gets there.

 

[pvanv]

Re: Nissan 9.8a2 running rich on top cylinder?

There is no substitute for the factory service manual. The test procedure for the ignition system is really involved with multiple values. Do yourself a huge favor, stop for now, order a manual from someone and just wait till it gets there.

Yep. You can order the Factory service manual, Part # 003N210561, for $40.00, from any dealer, including me. As Elvin noted, it could be anything... even a stuck or sticky ring...

You may find that the upper plug had a minor, invisible defect. I recently worked on a similar motor that was driving me nuts... with a cylinder that started OK but stopped firing after a minute. The warmer the motor, the shorter the run time. In the end, after some serious diagnosis... Turns out the owner had dropped that spark plug on the floor at some point, damaging the insulator internally.

 

[clintbeastwood]

Re: Nissan 9.8a2 running rich on top cylinder?

Will do guys thanks