5.0L timing - Maxum Boat Owners Club

rtw_ca · 09-07-2010, 01:46 AM

I have a 1998 3000SCR and one of my engines (STB) has an acceleration problem. I just had the carb rebuilt so it's not dirt. It idles well but as soon as I try to accelerate (slowly or quickly), the carb seems to starve of gas and begins to stall. I have to kind of pump the throttle and wait for it to start accelerating and then I can continue accelerating.

Also, I have trouble maintaining anywhere from 1000-2000RPM, it'll drop back to idle.

I suspected a timing issue or maybe a vacuum leak?

On the timing issue, I tried to locate the timing angle plate and I can't find it on either engine. Enclosed is a photo of where I thought it was but I can't see it. And even the service manual doesn't show it's exact location. Any ideas on the acceleration problem or on the location of the timing angles?

Thanks,
Richard

ed & inge · 09-07-2010, 11:14 AM

look in the fuel filter if there's water in to it, take it off put ut upside down in a glass pot and take a look. if there's to much water in the fuel filter it gets the water in the carb also and than.....its not running on heigh rpm's.......

greatz, ed

rtw_ca · 09-07-2010, 01:46 PM

Hi Ed,
I tried that and it's not water. In fact. I just got back from a 2 week trip on the boat where I put in about 5 full tanks of gas. So I'm really back to a mechanical problem. I even suspect my spark plug cables or a crack in the distributor cap.

Thanks,
Richard

rtw_ca · 09-10-2010, 08:35 PM

I spent the day on the boat and I found my problem! Under the carb is a plastic spacer of about .75 inches. Well the gasket UNDER this spacer had worn out at the back where it couln't be seen!Just so happened that I had another one and once I put it in, it worked like new! What a relief to find (and solve) our problems. A lesson for all with similar problems.
Richard

ed & inge · 09-10-2010, 11:11 PM

good job.....have fun again on the water.......and we have learned something again....

greatz. ed

cunuck · 09-11-2010, 01:26 PM

look at the v notch in the photo that is your mark for timing????

rtw_ca · 09-13-2010, 05:25 AM

That's what I figured. And when it lines up, that should be 10BTDC. I had never seen that in any of the mercruiser manuals nor on any Web site so I though I'd ask. But now that I hve resolved the acceleration problem, I don't think I'll pursue the timing issue.

Thanks for all the help.
Richard