150 ficht dies while trolling

[dhb31]

I have a 1998 johnson ficht engine with a updated power head and new heads use x 50 oil.runs fine all thru the rpm rangesmaxs at 5000 When trolling at 1000 to 1200 rpm runs fine for the the first hour to + or - 15 min then it sounds like is missing for a few seconds they rpm searges 3 to 4 hundred rpms then it dies checked the primer bulb while it is surging and it is firm.restarts at the touch of the key and idles smooth.resume trolling and about 15 min it .repeats it again the next time at 5 to 10 min. if i run it at high rpm for about a mile then it will troll normal for about 30 min and does the same thing again. Took it to the omc repair shop they r&r spark plugs changed fuel filter and primer bulb,ran on computer said it all checked out.PD the bill and they said if it still does it they recomend changing the ignition mudule another 500.dollars just for the part.what do you think about this DHB

 

[rodbolt]

Re: 150 ficht dies while trolling

if it was mine I would have them test it while it was acting up. parts changing gets expensive.<br /> troubleshooting is usually cheaper than parts swapping. unless you work a deal with them that if it does not work they pay for the module.<br /> good luck and keep posting

 

[steve n carol]

Re: 150 ficht dies while trolling

welcome dhb31,<br />ready for some fun w/others of like mind?..sl

 

[seahorse5]

Re: 150 ficht dies while trolling

Change prop to get close to 5500 rpm at WOT and then see how the motor trolls. You are a bit overpropped and that affects the whole range of operation.<br />The update kit said 5300 rpm but the motors run a lot better propped in the original 5500-5800rpm range.<br /><br />If you have the the FICHT Ram replacement powerhead (year 2000), then remove the exhuast pressure sensor and make sure it is not all carboned up.

 

[dhb31]

Re: 150 ficht dies while trolling

seahorse<br /><br /> thanks for the info on the 150 ficht ram replacement power head,<br /><br />Where do i lacate the exhaust pressure sensor on the 2000 power head

 

[seahorse5]

Re: 150 ficht dies while trolling

The 1998 FICHT has a finned computer that is air cooled. 1999 went to an all metal water cooled computer. 2000 and later had a water cooled computer with a large black plastic cover on it.<br /><br />If you have a 2000 computer there is a small rubber hose that goes down the stb. side of the engine block. Remove the stb. motor pan for access. Earlier than 2000 engines do not have an exhaust sensor.

 

[dhb31]

Re: 150 ficht dies while trolling

TO seahorse<br /><br />ficht 150 hp.my engine was up dated in july of 2000 new power head plus new heads(has set screw beside sparkplug)had to wait for 2 months for omc to make more replacemt power heads.so it should be a 2000,but as you discribed the computer i still have the orignal one with fins and no water cooling. whats next?

 

[seahorse5]

Re: 150 ficht dies while trolling

Sorry, with a "finned" computer, you still have the 1998 design motor, and NO exhaust sensor. Very few of the older FICHTs ever received the 2000 re-designed powerhead.<br /><br />Get a different prop and have a QUALIFIED tech doublecheck the throttle position sensor for any bad spots and to make sure it is adjusted to the correct voltage at idle. Also have the fuel pump diaphragm changed in case a pin-hole in it is leaking fuel into a cylinder, causing the surging. The diaphragm may be a stretch ( no pun intended), considering that you are idling for a while before the surging starts.<br /><br />Be sure to let us know what they find out.

 

[KorvetteKapitan]

Re: 150 ficht dies while trolling

I had an original Ficht 150, 1998 with something like your problem of surging,RPM fluctuation at slow speeds.<br />Check out the fuel vapor separator/chamber, float setting.<br />This needle/seat assy. can leak fuel into the throttle body housing which will raise your RPM's by adding more fuel than required for a given TPS setting.

 

[dhb31]

Re: 150 ficht dies while trolling

I had the ignition module replaced,by the same repair shop that i first took it to.took it out 10-07-04 trolled for 4 hrs never died or missed a lick have not changed the prop yet to get the rpm up but located 2 props i can try out before i buy one.thanks to all for the help