View Full Version : Maristar bogging out Please Help!

04-29-2007, 10:54 PM
I have a 95 maristar 200vrs and it is a TBI fuel injection system. The boat is bogging out on take off (out of the hole) and it won't open up and run at top speed. I have changed all of the following items:

1. PCV valve
2. TPS sensor
3. Temp control sensor
4. MAP Sensor
5. Cleaned Idle control sensor
6. Replaced fuel filter
7. Replaced plugs and wires
8. Replaced fuel pump
( I have checked the fuel pressure after the filter just before the Throttle Body and is measured 30 psi at all running speeds)

So, is there anything that you guys might be able to tell me!! I am puzzled and I believe I am going to have to take it to the nearest indmar dealer. Maybe they can tell me if the injectors are bad or maybe their computer will be able to detect something in the fuel or electrical system.

04-30-2007, 06:29 AM
First of all, I think your problems are seperate problems.

The over 3k rpm's, I'd lay money on, is clogged fuel line. If your V-drive has the same setup as my '95 PS190, there will be a fuel pump that looks like this:


(on mine, it's at the back of the motor). On that pump, if you take off the larger of the 2 brass looking studs, is a screen that will fill up with debris.

As for your "Won't start" problem, I'd look into your dead-man lanyard. They have a habbit of not working after a few years. Next time your boat won't start, take the lanyard off & push the button by hand while trying to start. If that doesn't work, I believe you can pull the wires off of the back & touch them together.

04-30-2007, 11:00 PM
I have a 95 Mastercraft Maristar 200 VRS. It has a 350 with TBI type fuel injection. The boat is bogging down at high RPMS and at load (coming out of the hole). It seemed to be a fuel problem, but I have done several things to fix it with no results. I replaced the fuel filter, cleaned the screen in the fuel pump, and checked for any blockage in the fuel lines. To make sure that the engine was getting enough fuel at the throttle body, I placed a valve from a fuel PSI testing kit in the fuel line just after the filter. I took the boat out to the lake and at key on I get 30 PSI. At idle about 25 PSI. While running it stayed at about 22 PSI. While running the boat it began to bogg at different RPM ranges. The fuel pressure remained at about 22 PSI. So, is this enough fuel pressure. If so, do I have an ignition problem? I plan on pulling all the plugs tomorrow to check them (probably replace them) and do a compression check on the cylinders. I am somewhat limited on what I can do with the fuel injection electronics. How can I code test it?

04-30-2007, 11:03 PM
I posted a new thread with some new info

05-01-2007, 12:02 AM
I think yours has a fuel return line and if this is true, your fuel pressure is low. It shouldn't drop much from maximum at any RPM. A momentary dip is OK but it should return to the normal range. As the poster mentioned in the other thread, your fuel line, filter, pump screen or fuel pickup tube is slogged. I saw this many times when I was working on boats and it was always something in the fuel system. If the previous owner ran it out of gas once, it may be OK but fuel pumps don't survive running dry more than that. OTOH, it could be the screen on the pump and the pressure numbers are similar to what I saw when that happened.

Use flare nut wrenches, don't "make do" with open-end wrenches, slip-joint pliers or adjustable wrenches.

You can use a regular OBD I code scanner for this. Unless you have a bad sensor, you probably won't see any codes but it won't hurt to try it.

If you think the plug wires are old, replace them, too. Don't go cheap- these motors are run a lot harder than a car or truck and good wires are important. Also, if you replace the cap and rotor, go with the Borg-Warner Gold Series parts. They have a 5 year warranty and are available at Checker, Auto Zone, Kragan and Schuck's. They won't help your fuel delivery problem but if you don't know the history of the boat, it's not a bad idea to replace them. If you can, do a vacuum test at the same time as the compression test and write down the stats for each cylinder, so you'll have a baseline to go off of.

05-01-2007, 12:15 AM

Try keeping just one thread going on the problems your having. It is very hard to follow both threads and make suggestions when you bounce back and fourth.

If all else fails, I am sure your local dealer would be able to help you out.

05-01-2007, 06:50 AM
Thanks for the suggestions,

Sorry about the posting two threads! I checked the screen in the fuel pump and cleaned it good. The in-line filter is new, and I am still having the problem. You guys said my fuel pressure is low, but the boat does not always bogg out. It will run at full power sometimes, and the amount of fuel pressure does not really change when the problem comes around. It might lose 1 to 2 psi. Is that enough to cause such a problem? I fell that the drop in fuel pressure is due to the drop in engine rpms. Not because the something clogged the fuel lines. Why would it run great, then bog, then run great, then bog again? I believe the operating psi on a TBI is 10 to 12 psi. That is what is in the owners manual. If that is the case, I have more than enough pressure at the TBI for the engine. I am right or wrong about this?

05-01-2007, 07:04 AM
Let me add one more thing. I know that the fuel pump is electric and is not affected by the engines rpms. I think that the fuel pressure will change based on the fuel consumpution of the engine. The more fuel being burn the less pressure? Or Should it be constant at its top number. The pump has 25psi max stamped on the side. I get about 22 consistantly.

05-01-2007, 12:44 PM
I have a 1994 Maristar 225 vrs with the TBI 350 that I just bought. When we went to water test it, it would bogg down over 2500 rpm, but run fine under that. It ended up being the TBI unit itself. It ran fine out of the water, it was when we put a load on it. Not that this is the problem, just something to think about.

05-05-2007, 03:03 PM
Up Date! I still need help.

OK so from reading different post I did the following things:
1. Changed plugs and wires
2. Replaced MAP sensor
3. Replaced Temp control sensor
4. PCV valve

All this and still not fixed. The boat runs better, but if you hammer down of the throttle coming out of the hole or run over 4200RPM the boat boggs. Coming out of the hole is ok as long as you don't hammer the throttle. If you just ease it down at first and then open it up it will work fine. I need suggestions. I checked the compression, and fuel pressure. These seem ok. Compression is about 110 on all cylinders, and fuel pressure is about 22psi.

Maybe the TPS sensor or the IAC sensor? What do you all think? What should the spray pattern of the fuel injection look like? I looked at mine and I am not sure exactly what it should look like. If the fuel injectors were bad, would the boat run good at certain RPMS and not at others?

05-05-2007, 04:32 PM
I don't know how you tested the compression but 110 is low. The motor needs to be at normal operating temperature, all spark plugs removed, injector fuse removed and when the key is turned, the first "pop' in the compression gauge's needle makes a big difference. Crank it over for a couple of revolutions and write the number down for the initial 'Pop" and also the max reading for each cylinder. The best thing to do is a cylinder leakdown test AND a vacuum test. If the cylinders are leaking down and the compression is low, full power won't be developed.

Going back to the fuel pressure issue, there is a pressure regulator on the fuel line and it has a thin vacuum hose attaching it to the plate below the throttle body. A leak in this will affect the pressure at high RPM/demand. A bad regulator can have the same effect.

I don't know how much has been spent on diagnosing this problem but if there's a MC/Indmar dealer nearby, having them connect it to their diagnostic computer will save time and money by eliminating some of the guesswork..

05-05-2007, 05:15 PM
Thanks for the post.

I guess my my of checking compression is not good. I do not feel that this is the problem. I don't see the pressure regulator your talking about.

05-05-2007, 06:03 PM
OK new update. I read JimN's post and I know the way I checked compression is wrong, but I am pretty sure my compression is good. I also read the part about the pressure regulator, and I figured out what he was saying. JimN you thought I had a Vortec Engine with TBI. My boat does not have a Vortec. So, I do not have that hose on the TBI. I looked at my friend's Supra SSV with TBI fuel injection. Her boat does have this regulator hose. I also looked that the spray pattern coming out of her injectors.

Low and behold! Her injectors are putting out a much better spray pattern than mine! I have an injector problem. They are not putting out a good spray.

What can I do to remeady this? I know I can replace the injectors, but I want to know the factory indmar part number. Is there anything other than clogged bad nozzles that can cause the injectors to spray poorly.

05-14-2007, 08:37 PM
Please read my new update at the very top.

05-14-2007, 10:47 PM
I never said anything about Vortec. Dump a can of Sea Foam into the tank and see if it gets better and then replace the first filter in the fuel line because if anything loosens in the tank, that's where it'll end up. WalMart and NAPA sell it.

If you need new injectors, the part number should be on them since they're standard GM/Rochester parts.

05-15-2007, 05:57 AM
Check on your pressure regulator for dirth and also look for bad conntact in the injectors plug. In my case, one injector was working on and off and dirth in the regulator. Since 3 weeks runs well.

05-15-2007, 06:46 AM
Check on the F.P. regulator for dirth and bad, conntac in one of the injector plug. There should be an "umbrella" shape spray from out of the injectors. I just fixed up one PS. few weeks ago. No news since.

05-15-2007, 06:50 AM
I suspect there is an injector problem. They are not putting out a good cone pattern. It is strange for both injectors to fail at the same time. The previous owner claims he had injectors put in. I have the reciept. I wonder if they used the wrong ones. Do you know if I can buy automotive injectors or do I have to buy the expensive indmar ones?

05-15-2007, 09:04 AM
Go back to the F.P. regulator. Looks like you have a leaking regulator. You might have dirth in it. Be carefull, it's easy to undo but you will have a hard time alone to put it back, because of the spring. Do not loose time, yuou have to do it one day, like I wrote it. Listen to JimN too, seems to me (as I am a new commer and do not know him) he knows what is he talking about. Also,you can plug the returne and check for like down. The returne line pluged, you should have 0 leak, or so. I think in this case 30 sec. would be OK. to see if functions right or no.
Good luck.

05-15-2007, 05:39 PM
JimN and breezy does my boat have a fuel pressure regulator? I was under the impression that it did not. I do not see one anywhere. It is not in any of the fuel lines and I do not have a hose coming out of the throttle body. Where would it be?

05-16-2007, 02:48 PM
Yes, you do have a fuel pressure regulator, right in the TBI. You have to open it and clean the bowl and see if it's not too worn out. Take care when you put it together, because of the spring pressure. Once you put it together,turne the key on and see if the pressure hold stedy for at least few min.If no you have found the problem.

05-16-2007, 09:09 PM
I know I am driving everyone crazy but you guys are great help and I really appreciate all the info!

Breezy, I found the regulator. It was just were you said. I did watch the fuel pressure and it did not hold up. It leaked down in about 3O seconds or so. I took the regulator apart and cleaned it. It was not dirty. Now it seems like it won't hold pressure at all. I can even here the return fuel bubbling in the fuel tank. It seems like it is going right through the regulator. I bought a new automotive regulator but it did not work either. It seemed like the pump pushed the fuel right through it as well. Is my regualtor bad? Why did the automotive one not work (maybe because it had a different pressure spring)?

05-17-2007, 12:48 AM
Yes, you did not get it together well! Get a hand from someone around you. One should push evenly the 2 parts together, which includ the F.P.R. and the cover and the other pers. screws it together. If you are off center (valve) when you assemble it, you will get a leak down. So this is what you got right now. Get it apart and when you reassemble, take care the membrane and the seal! I did it, so you CAN DO IT TOO! The pressure regulater is there to regulate the pressure! If not enough pressure, the injectors will not spray enough fuel (you will not have an nice, "umbrella" shape spray) so, your egine will not run well or might will not even start. MPI, should have about 35 to 40 psi, once you put the ign. key on and should hold on at least for 10min. I am not sure how much psi. should be on the TBI. So try to put it back together with someone.Take it easy and you will see that you can do it.

06-11-2007, 06:34 AM
check the throttle position sensor. Most likely it has three wires. To check for proper operation, disconect connector, test resistance with an analog meter between two of the wires.
Resistance should be as follows: 1
Short between two wires.
2. Another pair: operate throttle, the resistance should change smothly either going up or down.
3. Last pair: operate throttle, the resistance shoule be opposite test in number 2.

If it jumps the sensor is bad.