Force 95xr fuel or spark?

[JAKER95XR]

Timing is good ,mixture screws set.Fly wheel,stator,trigger,voltage regulator,rev limiter,auto enrichner,floats,inlet needles,plugs,motor ground is good all new parts.Motor at idle is loading up.When coming up off idle it seems like the motor needs to burn off the extra fuel to get going.It also shuts off at WOT full speed.Need some help.

 

[pnwboat]

Re: Force 95xr fuel or spark?

I assume that this is a 95 XR Sport Jet? If so which model...90HP 120HP?

1. Does it start OK, or do you have to crank it over for a long time to get it to fire?

2. Have you tried pumping the primer bulb at WOT to see if that has any affect? If it does, then I would suspect that the motor is starved for fuel. Need to make sure the gas tank vent is open and not closed or blocked. No obstructions in the fuel line or pickup inside the tank. Replace the fuel pump diaphragm, and if you have the fuel pump that is shaped kind of like a figure eight, change the 3 check valves.

 

[JAKER95XR]

Re: Force 95xr fuel or spark?

Its a 95hsp 3cylinder.I dont have a primer ball its a built in tank.I have recently rebuilt the fuel pump.It has all new fuel lines,floats,inlet needles.Would it hurt to put a primer ball between the tank and fuel pump.This boat new didnt have one?I will try the tank vents again also the pickup tube.Once the motor shuts off it will restart after a couple trys.

 

[pnwboat]

Re: Force 95xr fuel or spark?

Even with a built in tank, most of the older setups still have a primer bulb. It wouldn't hurt to put one on. Need to narrow it down to either fuel or ignition. Squeezing the primer bulb at WOT may help get you pointed in the right direction.

Also the fuel re-circulation system will affect low speed and initial acceleration. Make sure all the lines are flowing and the one way check valves are functioning properly.

 

[JAKER95XR]

Re: Force 95xr fuel or spark?

I started looking at my motor today.I checked the reeds they look great.Checked the tank vents again 3rd time for that ,all looks good there.Went over the recircullation system looks good.I did find two things that didnt look so good.One was the thermostat it was filled with little sticks and rocks.Also #1and#3 pistons looked good but #2 piston looked black and scratched on the sides.We did a compression test.#1-146 #2-149 #3-146 so that seems pretty good.Could use more info.

 

[pnwboat]

Re: Force 95xr fuel or spark?

What type of fuel pump do you have? Is it the one that looks kind of like a figure 8, or is it square? The one shaped like a figure eight has 3 check valves. These check valves are known to cause fuel starvation problems.

The other thing I would look at is the rev limiter. Is there a way to by-pass it?

 

[leeschaumberg]

Re: Force 95xr fuel or spark?

Hello
The carb setting in the book is the begining adjustment to get the engine runnng at start-up cold. After the engine warms up (5-10 min) it should be correctly readjusted.
The excess fuel & oil is fed into an ajoining cylinder via what is called the puddle drain rather than out the exhaust.
The engine stopping from WOT is usally caused from not enough fuel going to the engine through the main jet which can be reduced by gunk. With a primer bulb you can force more fuel in manually.
You said the timing was proper so the only thing left is spark plugs.

 

[JAKER95XR]

Re: Force 95xr fuel or spark?

Im going to get off the fuel problem for a second.I replaced the stator this past spring.The factory stator was black the aftermarket CDI stator is red.My question is, could the red one put out more power than the black one?If so could this mean that I would need a different voltage regulator than the factory regulator ,meaning one that can handle more power.I did replace the voltage regulator,with a new Mallory regulator.Should have went with the CDI regulator.

 

[pnwboat]

Re: Force 95xr fuel or spark?

What year is your motor? 1994, 1995, and 1996 there was some overlap in parts used for the ignition systems. Mercury was transitioning from the ignition systems that used the black switch box, to the CDM which have the coils integrated with the CD modules all in one package. There was also a 9 amp and 16 amp stator. The stator used with the ignition systems that use a switch box are different than the stators used with the CDM's.

 

[JAKER95XR]

Re: Force 95xr fuel or spark?

I have 1996 sport jet it has the CDM setup.I was wondering if the new stator was to strong and maybe screwed up my new voltage regulator?Just a thought.

 

[pnwboat]

Re: Force 95xr fuel or spark?

This would only happen if the voltage regulator was not one that was specified for the stator. If your DC voltage output from the regulator is around 13.5 to 14.5 volts at 2000+ RPMs, then it should be good. Do you happen to have the P/N's for the stator and regulator?

Do you have a vent tube/hose daisy chained to top of each carb fuel bowl that is routed to a port on the airbox? If the vents in the fuel bowls or the vent lines get clogged from old 2-stoke oil deposits, it will cause a rich running condition which is most noticeable when initially starting off. The float/needle valve in the carbs will not function properly because of too much pressure build up in the bowls from a clogged vent.

 

[JAKER95XR]

Re: Force 95xr fuel or spark?

Yes I do have the vent tubes coming out of the carb.And yes they are clean.I clean them every couple months,they seem to clog up evry couple months.I use the best oil Quicksilver makes.Here are those P/N.Stator-CDI 398-832075A21 Voltage reg-Mallory 2410259 or 9-17101 Trigger-CDI 134-8302-3 Rev limiter -CDI 144-1889-51 Fly wheel-Merc 261859236T14.All parts listed are all new this past spring.

 

[pnwboat]

Re: Force 95xr fuel or spark?

All of the part numbers are compatible. You have the stator that has the 16 AMP battery charging coil. The regulator you have is also the one specified for the 16 amp stator.

OK lets review what you've got here...It appears that most of your electrical components are relatively new (stator, rev. limiter, voltage reg., trigger). You say it cuts out at WOT. I assume that it runs fine as long as you don't open it all the way up? What is your WOT RPM?

One thing that comes to mind that may cause the motor to stop is if it overheats. You mentioned earlier that you found some sticks and rocks when you checked the thermostat. I wonder if you have an overheat alarm? If you do, you can test by shorting the Tan/LtBlu (not 100% sure about that color) wire from the temperature sensor mounted on the head to ground with the ignition key in the "ON" running position. This will cause the alarm buzzer to go off (if you've got one).

The other thing that comes to mind is the CDM's. With the engine idling, pull one plug wire off at a time. Each time you pull a plug wire off, the idle should drop and engine should not idle as well. If you pull a wire and it has no affect, I would suspect a problem with that cylinder. Usually weak spark caused by bad plug, or CDM. Sometimes bad reed valve, but you said that you checked them already. The CDM's all have a common "Kill circuit" wire (Black/Yellow) that are tied together. It's possible that a CDM is bad and possibly affecting the other two when you go WOT. Double check the 4 pin connector that goes to each CDM. Pull it off and look at the male pins in the connector to make sure one isn't partially pushed out.

 

[JAKER95XR]

Re: Force 95xr fuel or spark?

OK I have this motor all tore apart at least every thing on the outside.Everything I take off I triple check.I found a couple things that concern me.1st found a butt connecter from my trigger ground wire a hair lose.2nd found another ground wire from the main ground on the block that was either melted or rubbed down to the wire.I fixed both wires.3rd this is a question, on a fuel bowl the screw has two gaskets one inside the other outside both are very hard,should they be replaced?Could fuel sneak past the threads and get to much fuel?

 

[pnwboat]

Re: Force 95xr fuel or spark?

1. The butt connectors should not be loose, especially on the trigger wire. Trigger output voltage is only 1.5 volts on your particular set up. Low voltage, so any bad connection here could easily prevent your CDM's/coils from firing properly. You also might consider cutting off the butt connector and soldering an extension on that wire with an eyelet and attaching it directly to the block under an existing bolt. I'm not a fan of those butt connectors on the later model Mercury ignition systems, especially two yellow wires going from the stator to the voltage regulator. The clear plastic insulation that covers these two butt connectors usually show signs of being overheated.

2. If the other main ground wire just had the insulation rubbed or melted off, and it was still making contact with ground, you should be OK. Question comes up though....if it was melted off, what caused it to get so hot? Usually a poor connection/high resistance will cause this. Make sure you clean any corrosion off of both ends of the ground wire and the two points where it makes contact. If it was rubbed off, then make sure you take care of that so it doesn't happen again. It also doesn't hurt to add an additional ground wire yourself from the CDM mounting plate to the block. Good ground connections are critical to proper ignition system operation.

3. The two gaskets on the carburetor fuel bowl screw need to be in good condition. The outer one prevents fuel form leaking out of the bowl. The inner one seals the channel or cavity that the main jet sits in. If this was leaking, it could allow too much fuel to be sucked up causing a rich condition. They're pretty tough though. Not likely to leak if they're in one piece. Take a close look at it. If the inner one looks questionable, by all means, change it. Cheap fix.

 

[CharlieB]

Re: Force 95xr fuel or spark?

You may have two separate fuel problems.

First, idle mixture needs to be adjusted, it may be slightly too fat. Adjust idling in Forward to achieve best idle speed, then further open each screw 1/8 turn. Test acceleration from idle, any slightest hesitation, bog, lean cough, then further open mixture screws 1/16 turn, repeat acceleration test until all traces of hesitation are gone.

Second, test WOT performance with a remote fuel tank. The check valve in on-board fuel tank fittings have been known to clog, restricting WOT fuel flow.

 

[JAKER95XR]

Re: Force 95xr fuel or spark?

When you say adjust idle in forward to achieve best idle speed,do you mean move shifter forward and if so what RPM range?Also the check valve on an on-board fuel tank ,do you mean the anti-syphon valve above the pickup tube?If so my boat doesnt have one.

 

[CharlieB]

Re: Force 95xr fuel or spark?

Adjust idling in Forward to achieve best idle speed, then further open each screw 1/8 turn. Test acceleration from idle, any slightest hesitation, bog, lean cough, then further open mixture screws 1/16 turn, repeat acceleration test until all traces of hesitation are gone.

Fuel tank Dip tubes can have a screen over the end or fiberous material inside, either can clog with sediment, trash, whatever, and restrict WOT fuel flow.

Fuel lines HAVE been known to be restricted by too tight a zip tie holding the hose alongside a wiring harness.

ANY restriction can limit WOT performance, too great a restriction and the upper cyl's start burning lean enough to melt the piston.

 

[JAKER95XR]

Re: Force 95xr fuel or spark?

Thanks pnwboat your a big help.I was at a local Mech. and he checked his computer for service bulletins from Merc on my boat and it said to run a ground from the block to the ignition plate.I did that.All my ground wires come from one bolt on the block.My ignition components on the ignition plate are all grounded to one screw on the plate with the wire I ran from the block.Could there be to many wires on these two bolts?

 

[pnwboat]

Re: Force 95xr fuel or spark?

Yes, the ground connection is a little weak in my opinion. The single bolt that was the original ground connection is just threaded into the ignition plate. It's not a very large bolt and the ignition plate is not very thick so there isn't much thread there. It's easy for it to work it's way loose. They should have used a larger bolt with a nut and lock washer on the other side of the ignition plate so that you can really torque it down tight. Make sure you scrape away any paint under the bolt head to insure a good connection.