98 FICHT 150 rough idle/engine miss

[sunbird 18]

Just got this boat/engine. 3rd time taking it out. Ran fine 1st day, 2nd day I noticed a bit of sudden random power loss (drops 100rpm) at cruising speed(3500rpm) muffled backfiring noticed. It feels like it drops a cylinder for 5 sec or so then picks it back up. cold starts have been getting more difficult. I changed out a stuck open t-stat and changed the plugs. Took her out today and no difference. Still dropping a cylinder and getting even more hard to start/rough idle. Pulled her out of the water and flushed it out and noticed that the engine is missing! While the engine is running, I pulled the plug wire off the top left plug and it made NO DIFFERENCE!! Pulled the middle plug on the left side at the same time and STILL NO DIFFERENCE!! Its missing on 2 cylinders! Any other plug wire removed and the engine stalled. When out on the water, it seemed to be running decent at mid rpm-WOT, maybe a bit less holeshot, but still not too bad.

checked the plug spark and all spark strong....hmmmm.....

Seems to have all the upgrades, pinned heads, soft fuel rail lines, but still running air cooled EMM. Compression shows 110 on all on the right, 100 on all on the left.
ANY IDEAS???

 

[JB]

Re: 98 FICHT 150 rough idle/engine miss

I am deathly afraid of the late 90s FICHTs, particularly the 150. Son in law blew up three of them (all '97s) in less than a year. He then got a carbed ('98) 150 that is still humming like new with around 1200 hour on her.

I don't think you will like my suggestion, but get rid of that and put a carbed 150 on.

 

[blackbox]

Re: 98 FICHT 150 rough idle/engine miss

this motor can be hard to trubleshoot without a laptop and diag. software and cable and a factory shop manual. you can use the old ev.diag. 142B software loaded on an old windows 95or98 operating sys. the best software is the new b.r.p e-tec 2.0 or 3.0 loaded on a laptop with xp. if you do not have acess to diag. software all is not lost. here is a cuple things to try: #1 get a spray bottle with gas/oil mix in itat a 50:1 ratio. at idle with air box removed , spray a little gas in each intake. the r.p.m will rise or change. (if 5 cylinders act one way and no change on the other= will help pinpoint the problem cyinder.) note: this motor will "run-away" if you introduce to much fuel in to the motor! #2 if you get someone to drive the boat you can try spraying gas in the intake at diffrent speeds. all cylinders should react similarly. #3 this motor has 24volt injectors. if your 24 v. system is low it can affect fuel injection and running quality. #4 pump up the primer ball. pressure test fuel system: it should hold 5 to 6 psi. if it dose not ,chk. the fuel pump diaphram. #5 please note that it can be hard to repair this motor with out the right equipment and tools. you may want to find a good evin. tec. to tell you what the problem is. do not put a lot of monry in this motor. they are prone to issues: e.c.u and regulator failures, power head failures , fuel pump problems(diaphram) . i hope your problem is a small one.

 

[sunbird 18]

Re: 98 FICHT 150 rough idle/engine miss

this motor can be hard to trubleshoot without a laptop and diag. software and cable and a factory shop manual. you can use the old ev.diag. 142B software loaded on an old windows 95or98 operating sys. the best software is the new b.r.p e-tec 2.0 or 3.0 loaded on a laptop with xp. if you do not have acess to diag. software all is not lost. here is a cuple things to try: #1 get a spray bottle with gas/oil mix in itat a 50:1 ratio. at idle with air box removed , spray a little gas in each intake. the r.p.m will rise or change. (if 5 cylinders act one way and no change on the other= will help pinpoint the problem cyinder.) note: this motor will "run-away" if you introduce to much fuel in to the motor! #2 if you get someone to drive the boat you can try spraying gas in the intake at diffrent speeds. all cylinders should react similarly. #3 this motor has 24volt injectors. if your 24 v. system is low it can affect fuel injection and running quality. #4 pump up the primer ball. pressure test fuel system: it should hold 5 to 6 psi. if it dose not ,chk. the fuel pump diaphram. #5 please note that it can be hard to repair this motor with out the right equipment and tools. you may want to find a good evin. tec. to tell you what the problem is. do not put a lot of monry in this motor. they are prone to issues: e.c.u and regulator failures, power head failures , fuel pump problems(diaphram) . i hope your problem is a small one.

Hey, welcome to the forum and thanks for all the good ideas! This forum needs more people like you who offer well written technical feedback and procedures instead of useless, unfounded opinions that really dont help the OP. Thanks!

 

[blackbox]

Re: 98 FICHT 150 rough idle/engine miss

very kind words! thank you.