98 300 PM ignition problem

[Dean Dorsey]

Boat seemed to be running a bit slugish not horrible just down about 3-400 rpm, I wrote it off to hot weather. I put a timing light on it and it showed that the timing was not advancing. No matter where the throttle was it showed about 6-8 degrees BTDC. It also seemed to have weak and sometimes intermitant spark on 1,3,5. Is it possible for a hull to make it to within 5mph of normal with timing stuck in this range? Also seems to start harder than it did, I have to use throttle and about 3-4 tries where before it was one. There is visible spark on all 6 fairly consistant. I'm thinking ECM, or crank sensor if it is possible for one to go out, maybe even a TPS. Anyone had similiar problems? I don't have access to a DDT but was hoping for some inexpensive ideas as where it is logical to start. I will pray it's not the ECM. All timing readings were taken with the motor off at cranking speed, with fully charged batteries. Any help is much appreciated. Thanks, Dean

[Liquid Force]

Have you changed the coils?? or are you running the early black wire coils?? THe 98 300PMs had quite a few problems with the coil setup and did funny things with the timing i.e double firing, you can replace and update them with the later model grey wire coil packs not cheap about $700 for a set but I would assume thats the problem, see if you can borrow another set of coils and see if that fixes the problem.

James

[Dean Dorsey]

Thanks liquid, I was thinking the same thing a bit ago. I believe it does have the black one still in it. I have heard there were problems with them. Was going to change them out over last winter but the $$$ stopped me. I will see if I can further isolate the problem to the coils. Again Thanks, Dean

[Euroski]

I would find it odd that all 6 coils are firing with incorrect timimg, but I guess it can. I purchased mine from my Mer dealer and got all 6 for under $400! Engine runs alot smoother since the change.

[Dean Dorsey]

Euroski, That is a good point, I only indexed for piston #1 the rest I tried to eyeball. But I was getting intermittant spark on all six, sometimes good and sometimes not at all. This leads me to believe it may not be coils, but I do need to change them out as they are the black ones. I am going to do some switching around and test again. Although coils may be part of the problem I still believe the root is now possibly the ECM, and that possibly the coil misfires created an ECM problem. If anyone has a good one for sale, please let me know. Thanks, Dean

[Liquid Force]

Talk to Eric from Simon motrsports or Wanye From Madefi, both of them are pretty well versed in the 3 litre motor's they would be able to point you in the right direction.

[Dean Dorsey]

Liquid, Will do most of the motor is Eric's stuff and the rest is Wayne's will give Wayne a call tomorrow. Thanks, Dean