1998 Johnson 150 hp Ficht Fast Strike

[Wild Bill]

Hi every one,need a question answered. At idle my engine runs smooth and when running 3000 rpm and above it also runs smooth but between 1500 and 2800 it has a miss like a spark plug is bad. I always clean the plugs every time before I go out and I also index the plugs. Any ideas would be greatly appreciated.

 

[Jimmy Saunders]

Re: 1998 Johnson 150 hp Ficht Fast Strike

Whats up Wild Bill?<br />If I were you I would by new set of plugs and stop cleaning them. I change the plugs in mine every year and lower unit oil. You maybe over cleaning your plugs.<br /><br />Later Bassin JIm

 

[muskrat]

Re: 1998 Johnson 150 hp Ficht Fast Strike

what's the model & serial numbers

 

[seahorse5]

Re: 1998 Johnson 150 hp Ficht Fast Strike

What plug number are you using? Does the motor have the "pinned" head update? You can tell if there is an "allen screw" set in the head close to each sparkplug.<br /><br />Most likely the rough spot is the transition stage when the engine switches from low power to high speed combustion. It was very noticable in the original motors and a bit better in the updated ones. They redisigned the FICHTs in 2000 and got rid of the roughness.<br /><br />Changing props, which is the load on the engine, can help alleviate the roughness or move it to a lower rpm range that you do not run it.<br /><br />What is your top rpm with a full load of fuel?

 

[Wild Bill]

Re: 1998 Johnson 150 hp Ficht Fast Strike

Thanks guys for your input, I really appreciate it. I'll answer your guys questions the best I can.Bassin Jim, I just clean the plugs with alittle gas and recheck the cap. I've only had the boat since December 2004 and new plugs were put in. Muskrat, my model #J150ILEC,<br />Serial # G 04469708, the heads are pinned, up graded. Seahorse, I haven't pushed it pass 5000 rpm as I'm going 50 mph. I still have maybe 500 rpm's left.50 mph is to fast for me so I back off to about 40mph. I have the XC12PEPB spark plugs.It really runs great at hi and low rpm's.The more I ask question the more I learn from you guys.Thanks again.

 

[seahorse5]

Re: 1998 Johnson 150 hp Ficht Fast Strike

Next time you are running it and the conditions are safe, give it a short blast of full throttle. As long as the motor will turn 5300-5500 rpm, or even a "schoshe" more, you are in good shape.

 

[Wild Bill]

Re: 1998 Johnson 150 hp Ficht Fast Strike

Thanks Seahorse, I'm going out next week and I'll give it a try.

 

[muskrat]

Re: 1998 Johnson 150 hp Ficht Fast Strike

is it dropping rpm when it missing or running rough

 

[Wild Bill]

Re: 1998 Johnson 150 hp Ficht Fast Strike

muskrat, I really didn't notice rpm"s drop as I wasn't looking at the rpm, I should have. It runs alittle rought but not real bad,kinda like a hesiation but then clears up with more rpm.What could it possibly be if my rpm's drop?

 

[muskrat]

Re: 1998 Johnson 150 hp Ficht Fast Strike

IT SOUNDS LIKE THAT IT GOING TO BE THE NATURE OF THE BEAST,JUST LIKE SEAHOUSE WAS SAYING,IT A TRANSITION STAGE.IF IT IS NOT DROPPING RPM.

 

[Wild Bill]

Re: 1998 Johnson 150 hp Ficht Fast Strike

Thanks Muskrat for your help, I will check out every thing when I take it out next time.

 

[simonexyz]

Re: 1998 Johnson 150 hp Ficht Fast Strike

Hello,<br />Is it important if the engine is not able to reach higher than 5000 rpm? is it the symptom of some serious problem ?<br />A couple of days ago I tried a boat I would like to buy with a 150 FICHT that was unable to reach higher than 5000 rpm.<br />(I have not investigated about the "pinned head" upgrade yet beacuse only today I've read about it on this forum)