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98ps190
03-16-2006, 03:23 PM
Towards the end of last season my boat would start right up, and on occasion idle higher than normal. The only way to fix this was to turn it off and start it back up. I would say this happened once every 10-15 starts. It did it more from cold starts than with hot. Other than that, boat ran well. Thanks for the input.

east tx skier
03-16-2006, 03:26 PM
Do you have perfect pass?

98ps190
03-16-2006, 07:41 PM
No PP (by PP on mean Perfect Pass and not.......you know!)

JimN
03-16-2006, 08:13 PM
If it goes into fast idle again, while it's still running, remove the flame arrestor and look at the throttle plate. If it's not closed, see if it will close by removing the throttle cable. There's a metal sleeve that keeps the cable end form sliding off of the ball on the lever. If this fixes it, the throttle linkage may be a bit sloppy and sticking. Or, it just needs to be adjusted. The other possible cause is the IAC (Idle Air Control) and it may need to be reparked. I'll see if I can find the info for doing this. It's not something you want to pry on. If it never happens when the motor and air temp are warm, it could be that the IAC is just sticky. Also, look at the PCV and breather hoses for cracks or looseness. Any air leak under the throttle plate can cause this problem. Is there any hesitation when you accelerate quickly?

Sodar
03-16-2006, 08:25 PM
If it goes into fast idle again, while it's still running, remove the flame arrestor and look at the throttle plate. If it's not closed, see if it will close by removing the throttle cable. There's a metal sleeve that keeps the cable end form sliding off of the ball on the lever. If this fixes it, the throttle linkage may be a bit sloppy and sticking. Or, it just needs to be adjusted. The other possible cause is the IAC (Idle Air Control) and it may need to be reparked. I'll see if I can find the info for doing this. It's not something you want to pry on. If it never happens when the motor and air temp are warm, it could be that the IAC is just sticky. Also, look at the PCV and breather hoses for cracks or looseness. Any air leak under the throttle plate can cause this problem. Is there any hesitation when you accelerate quickly?

Jim, that would be great if you could find the info on the IAC. It seems as though I have the opposite problem though, when I am idling back to pick up a skier (about 1000 rpm's) and pull the throttle back to neutral, the engine hesitates and on occassion dies. I have been to the dealer a few times with the problem, but they can not reproduce it on the trailer... maybe I can figure it out myself!

JimN
03-16-2006, 09:05 PM
You have a PCV valve- has it ever been replaced?

Sodar
03-16-2006, 09:54 PM
No, the PCV valve has never been replaced since I got the boat (about 3 years and 300 hours ago). Is this a common replacement part? If it is, I am suprised my dealer did not change it.

98ps190
03-16-2006, 11:02 PM
JimN
If I go from idle to full throttle there is the slightest hesitation. Also if I run wide open for any length of time the boat will cut out very quickly every 10 sec. or so. I'm still able to reach approx. 44 mph. I've owned the boat for 3 years and it's never had a tune up.

east tx skier
03-16-2006, 11:37 PM
Trottle cable binding would've been my guess. I asked if you had perfect pass because when mine would do this, if I killed the ignition, when I restarted, the perfect pass servo would wind up and tighten the slack out of the cable. But coming off higher rpms, the cable would bind and hang at about 1,200 rpms. Turned out that the cable was not level, causing it to bind.

If it's cutting at higher speed, it could need a new fuel filter or maybe clean the fuel pickup or flame arrestor.

Just spit balling.

JimN
03-16-2006, 11:40 PM
If you've had it for that long and you haven't tuned it up, when do you suppose it was tuned up last? If you don't know, it needs attention. If you use it close to 80 hours/year and you haven't tuned it up, it's borderline neglect. How often do you change the oil? Has the fuel filter been changed in the time you have owned it? How about the transmission filter and fluid? If you have the manual for your boat, there's a section in the back that lists 25, 50 and 100 hour checkup service. If you haven't done any of it, do it soon, There's a reason they put that list in there and it's not so they'll have something to write.

The cap and rotor, plugs, wires, filters, shaft packing, etc won't last forever and the tuneup parts should at least be checked annually. Plug wires are good for about 3 years if the boat is used more than about 100 hours, depending on how hard it's driven, weather, chemical exposure or anything else that could shorten their useful life. Good tuneup parts make a difference. Cheap ones can cause damage due to crossfire and other issues (like just being cheap parts).

Sorry if this sounds harsh, but if/when your car runs bad, do you just ask people what the possible causes are? I doubt it. Your boat has a car motor in it and needs the same kind of service, just more often based on the hours of use. Cars aren't usually run at WOT while boats frequently are. This stresses everything from the oil, oil pump, plugs, wires (ignition spark frequency changes when plug wires are used for too long and performance drops off), fuel pump, cap/rotor, belt(s), pulleys, brackets and every internal engine part.

Tune it up, use the right parts and do it when it's supposed to be done. I use Borg-Warner cap and rotor (get the better line of their parts- Checker sells them and IIRC, they have a 5 year warranty). Taylor wires were on the motor when it was shipped to the dealer and they work great. AC MR43LTS plugs (LT-1) and if someone can help out here, I don't recall what the TBI used in '98. I think it was MR43TS. AC GF-626 for the fuel filter on the motor and there's another one on top of the tank. Which motor is in your boat? It's not in your profile.

You have a screen on the fuel pickup tube and in '98 they had some issues with carpet fibers that got into the tank during assembly, so that and the screen at the inlet of the fuel pump need to be checked for blockage. Change both fuel filters, not just one of them. Some models have only one filter, so you'll need to look at the tank. If you don't see one there, don't worry, they didn't hide it anywhere else.

There's a slight chance that you have a bad sensor, but if you haven't done any other service to it, I wouldn't really suspect them.

Doug- thanks for mentioning the flame arrestor. This is probably the single most neglected item on all of the boats I worked on. DIrty flame arestor is like running with a piece of duct tape over your mouth.

One of the local boat dealers recently had a used boat sale and on every one I looked at, the flame arrestor was filthy, including the one a friend bought. His has a Mercruiser 4.3 LX and hadn't been maintained well at all. Bent prop shaft, skeg and prop were gished, gelcoat was WAYYYYY oxidized and it had Autolite plugs in it, two of them had the gap at about .060" and were totally black. Oil was changed whenever. Put new plugs in it after gapping them and it kicked over with no problem.

98ps190
03-17-2006, 10:00 AM
JimN
Thanks for the advice. The motor is a 5.7ltr vortec. I do not know when the boat was tuned up last. I've put around 75 hours on the boat since I've owned it. I've changed the oil/filter, and trans fluid at the end of each summer. I have not changed the trans filter. I've had mechanic friends look at plugs, wires, etc. and they've said that this spring they should all be replaced. I haven't had any engine/trans issues until the end of last season. I will replace the things you have mentioned in your previous posts.

It would be really easy to just drop it off at the dealership and tell them what is wrong and what I need done, but as many of you know, it's not that simple. They'll say; sure, we can get it in around july and you'll have it back sometime in August and it'll cost around $1000. This is no excuse for not doing preventative maintenance, but I think you can see my point. Thanks again for the advice.

JimN
03-17-2006, 10:47 AM
Again, I'm sorry if my post sounded harsh, but it just sounds logical to me that if something mechanical is not maintained for three years, things will happen that aren't always right. 75 hrs in 3 years isn't very much use but there are still some things that absolutely need to be done. Just like a car, if a motor isn't run occasionally, seals tend to dry out and leak or fail so even if you can't go boating, I would run it till it gets to normal operating temperature for awhile.

Doing a tuneup on a motor like this isn't hard. If you have any mechanical ability at all, you should be able to do it (if you want to). Since you have friends who are mechanics, maybe they could either give you some more pointers, help out or actually do the major things for you. The spark plugs are specifically for marine use, so I strongly recommend using AC MR43LTS. If the auto parts store doesn't have them, they can get them for you. They have a stainless body and won't rust in place the way regular car plugs can. Again, the flame arrestor could be a major player in your problem. It comes off by loosening the hose clamp and rotating it while it's slid off. It can be cleaned with carb cleaner (I like NAPA cleaner in the blue can).

If you're going to an actual MC dealer and they can't get a boat done in a month, either they have way too many boats to do, they're totally understaffed, they're bad at scheduling and managing the service department or they just don't get it. If you could call early in the year and get it on the schedule, they should be able to do the work faster. Admittedly, July is peak boating season, but they should still get 'em in and get 'em out (repaired correctly and thoroughly, of course).

I hope gas stabilizer has been put into the tank every year because gas goes bad when it sits. It gets gummy, the octane drops and performance suffers. Before the fuel filter is changed, depending on how much gas is in the tank, find a place that sells Sea Foam and put in as much as the directions indicate, based on gas volume, then use up as much as you can. If you open the filler cap and it smells distinctly different from good gas, you may want to have it emptied and start over, with the gas properly disposed of. Not the cheapest way to go but it would be better for the motor. Once the Sea Foam has done its job, fill with fresh gas and add stabilizer so it doesn't go bad again. It can't sit idle indefinitely, though.

One thing you may want to consider is the fact that if the previous owner ran out of gas repeatedly, the fuel pump may be going bad. Not your fault, but it becomes your problem since you now own the boat. The fuel pressure should be checked to find out if the pump is able to do its job the way it should. Does your gas gauge stick?

98ps190
03-17-2006, 11:30 AM
JimN

Again, I really appreaciate this forum and the years of experience most people have with Mastercraft.....I, unfortunately am not one of them.

I have winterized the boat each fall following the advice of users on the forum. This did include running stabil thru the fuel system. My fuel gauge stopped working two summers ago. I pulled out the sending unit and found that the float seemed to be hung up on small metal burr. I cleaned it up put it back in and haven't had a problem since. During the summer the boat is run about once a week, it's just not for more than an hour or so. This is with the boat in the water, so it does get up to normal operating temperature.

Should the flame arrestor by secured around the throttle body? Mine seems to just sit on the lip with the only connection being (what I think) is the vent hose.

Are the tune up kits offered thru DIM good enough for my boat?

Thanks again

JimN
03-17-2006, 12:04 PM
The float probably was affected by the gas you have available in your area, if it's reformulated. There were a lot of problems back then because of it and a lot of sensors were repaired/replaced because the float would expand and bind. If you didn't use at least one full tank each year, you have a lot of stabilizer in the gas, more than what the mix calls for. This could be part of it, too.

Yes, the arrestor should be secured- its purpose is to suppress flame from backfiring and if it's not secure, the pressure would pop the arrestor off and allow subsequent flame to cause an actual fire. If yours is black or grey plastic with a rectangular metal grate (very thin ribs), there should be a hose clamp at the base, holding it onto the throttle body.

I never bought anything from SkiDim because I get parts through suppliers, but there's nothing needed that you can't get locally. Also, you have the LTR, which doesn't even have a distributor, so you don't need to worry about that. You need fuel filter(s), spark plugs, wires, oil and filter, trans oil and filter, clean flame arrestor, and you're basically done. You can't even reset the timing (not adjustable at all unless it's done in the ECM program), so that's not an issue, either.

If you lose spark completely, it would probably be the safety switch or it could be the crank sensors, but you haven't said this was happening.


In your initial post, you said the high idle was happening on cold starts- how cold? If it was less than 50 degrees or if the idle speed dropped within about 15-30 seconds, it's normal. Cars do the same thing, based on the ECM telling it to idle that fast to speed up the warmup period (just thought of this). A hesitation during hard acceleration usually comes from bad fuel filters or pressure (can be from the same thin). Old plugs and wires could still be the cause too, and it's about time they were replaced.

Where do you use the boat?

east tx skier
03-17-2006, 12:31 PM
Jim, if his is the TBI, I think the hose on the flame arrestor is held on by little barbs on the attachment point at the rear of the flame arrestor. My father-in-law's doesn't have a clamp on it. Of course, it could have mysteriously disappeared. I only remember this as I'm the only one that ever ends up cleaning his. ;)

98ps190
03-17-2006, 03:51 PM
JimN

I should have been more careful in my previous post. 5.7 litre. I don't have the LT-1. I have the TBI 350ci Indmar motor.

As for fuel, I live in lower michigan and use much more than a tank a season. When the high idle happens, by cold I mean the boat hasn't been run in a few days. Air temp is at least 70F. I don't think I've ever let it run for more than 30 sec at the high idle to see if it would come down on it's own. I will try that this spring.

JimN
03-17-2006, 05:56 PM
Oh, I thought your post said it was an LTR, not TBI.