Sierra parts?

[LiquidTherapy]

Anyone ever have any problems with Sierra stuff? I built my carbs and fuel pump with Sierra stuff. I fixed my starting problem, but my top end running is a issue.

Motor is a 86 merc 150 xr2. Idles great and runs up till about 3000 rpm. After that it Will run the bowls dry(best I can tell). If I throttle back and let pump catch up I can go back to full throttle. It will run for 30 secs or so again and slowly loose rpm. Primer bulb is hard, and clear filter after the bulb is full.
I hate to just buy a new pump being it is over a hundred bucks.

The reason I'm asking about Sierra stuff is a guy at a merc dealer was giving me hell aabout Sierra stuff. Mainly the needle and seat. Any ideas?

[GoneFission]

The OEMs always talk trash about all non-OEM parts.  But sometimes they come from the same manufacturer.  A friend of mine owns a company that makes spark plug wires - they sell to everybody - GM, Ford, and all the aftermarket brands.  Sometimes there are differences, like MSD requires the best specs in the industry for spark plug wires.  In other cases, several brands all get the same product.  

I have not had problems with Sierra parts, but your problem may not be the fuel pump.  Check all the lines and make sure you have tight connections.  The fuel starvation problem you describe can easily be caused by air leaking in through a loose hose clamp or a cracked fuel line under the cowl.  The fuel pump will pump air before it will pump gas, so a small air leak in a line can cause exactly what you are experiencing.

[fitz73222]

The engine would be surging if it was starving for fuel. The needle and seats are open at high speed unless they're sticking shut or the float heights are set incorrectly. Did you soak the carbs in carb cleaner before you rebuilt them to make sure there was no varnish or debris left behind? On the outset that your engine has the original 2 stage black or blue stator, that very likely could be the problem. If it has the red stator it's been replaced. Get the stator checked for voltage output or a short. 3000 rpm was the number when the old style stator went from low speed to high speed mode, so it may be more than coincidental. If you need to replace the stator, get one from CDI and not Mercury. It's lower cost, 2 year warrenty and better. Mercury stators suck and they haven't used your style of ignition since '97. Also get your switchbox's checked, you have 2, you could be losing a bank of cylinders but that usually effects low speed running quality as well.

[fitz73222]

As for the original Sierra question, I've used them for years without issue. The only thing I've consistently seen is slightly lower water pressure with their impellers, must be slightly different durometer rubber. Nothing alarming just an observation.

[wingtime]

I think Sierra parts are fine. I had a dead out of the box coil once, but that happens with oem  stuff too. I feel that in some cases the oem  parts are better and other cases the aftemarket is superior. I agree that when it come to ignition parts Cdi is  far better than stock.

[LiquidTherapy]

The engine would be surging if it was starving for fuel. The needle and seats are open at high speed unless they're sticking shut or the float heights are set incorrectly. Did you soak the carbs in carb cleaner before you rebuilt them to make sure there was no varnish or debris left behind? On the outset that your engine has the original 2 stage black or blue stator, that very likely could be the problem. If it has the red stator it's been replaced. Get the stator checked for voltage output or a short. 3000 rpm was the number when the old style stator went from low speed to high speed mode, so it may be more than coincidental. If you need to replace the stator, get one from CDI and not Mercury. It's lower cost, 2 year warrenty and better. Mercury stators suck and they haven't used your style of ignition since '97. Also get your switchbox's checked, you have 2, you could be losing a bank of cylinders but that usually effects low speed running quality as well.

Thanks for the replies...No actually I did not soak them. They where pretty clean. Cleaner, compressed air, and torch tip cleaner. The only issue I found originaly was; Top carb had a aftermarket float that would hit the bowl. Not sure if it was hanging up. But it was replaced with new. Also the bottom had a float that was half full of fuel. It to was replaced. Motor cold starts easy now, primer line was kinked Idles all day, low end to mid range perfect. Top end is great for about 30 or so seconds. Then slowly starts loosing rpms. If I back down to around 2k rpms for 20 to 30 seconds I can hammer down again for my 30 sec. of blistering speed. Playing around today, I put a fuel pressure gauge on the motor. I had about 1 to almost 2 psi at idle, I didnt run the boat in the water just had the foot in a large tub with water running into it. A few blips of the throttle and NO change. I pulled pump off and really looked at it. I think the check valves might be a issue. Not a good test, but I can blow and suck throw both. I figured why not order a new kit with valves. Original was just gaskets.

On that note can I use the new square style? I read some where it pumps a bit more fuel. Just a thought.

Other issue I have noticed and read about is the awesome charging system, or the lack of. Idleing out of the river with the lowrance and the vhf on I am showing 12.0 on the lowrance display. While I was attempting to haul azz i seen as high as 16 volts?? Battery is about six months old. It was charged the night before this. The low voltage at idle worries me, I can see trolling for a hour. Then cut the motor of and low and behold dead battery. Best I can tell it is the 16 amp system and the stator is black.

Thanks again guys!
Don

[fitz73222]

Hey Don,
16 volts is way to much, should be 14.5 volts at high speed and 12.5-13 at idle. I would be looking at testing the rectifier/voltage regulator. This could also cause the stator to overheat and give you an ignition issue since the stator produces charging voltage and ignition voltage and heat = resistance. Amazing that it still has the black stator, most never made it past a couple of years. As far as fueling, replace the diaphragm, gasket and check valves in the original fuel pump. 1-2 psi at idle is normal but since you want to eliminate the pump as the issue, go ahead rebuild it. Did you try having someone pump the primer bulb above the 3000 rpm thereshold and did the engine respond? This momentarily force feeds more fuel into the engine and if it's starving, the engine should speed up. Did you replace the inline fuel filter under the cowl assuming it still has one? That saturated float you mentioned spells ethanol damage so all of the fuel lines are suspect for collapse and jammed with chunks of degraded fuel line, I have absolutley experienced this. I'm still leaning towards the bad stator theory since the engine runs so well up to 3000 rpms and you still have the original stator. Nothing wrong with eliminating a fueling issue in the meantime.

[LiquidTherapy]

I will do some checking. All lines on the motor are new. Filter is new. I wasn't able to pump bulb while running. I was out with my 7 and 5 year old boys. Maybe I'll have oldest try. Before I built carbs, the first outing when the motor slowed and then died I tried to pump the bulb. It was full and hard. The inline filter right after the bulb is full. That first time I had to choke it to get it to crank. Thus leading me to fuel problems.  
After ready ing so much bad about the charging system. I was almost ready to just buy new stator regulator and rectifier. I would rather not waste the money but I do want it reliable since it is pretty old. Thanks again. Hopefully I can get something going this week. I hate time change!

[GoneFission]

"awesome charging system, or the lack of. Idling out of the river with the lowrance and the vhf on I am showing 12.0 on the lowrance display. While I was attempting to haul azz i seen as high as 16 volts?? Battery is about six months old. It was charged the night before this. The low voltage at idle worries me, I can see trolling for a hour. Then cut the motor of and low and behold dead battery. Best I can tell it is the 16 amp system and the stator is black."  

There were 2 charging systems used on your motor - a 9 amp system and a 16 amp system.  The motor makes very little amperage at idle - 12 volts is about all you will get - you may see less than 12 volts if you are running lots of electronics, livewell pumps, etc. - the stator-based charging system just can't keep up with that stuff at idle.   :x   The 9 amp system does not have a voltage regulator, so 16 volts is very possible after the battery is charged.  The 16 amp system does have a voltage regulator that sits on top of the engine.  The Mercury voltage regulators are a weird design and very expensive - some folks just disconnect them if they are running much in the way of electronics    but that could lead to over-charge if you run longer distances with the 16 amp system.    

The battery will not go dead at 12 volts and you can usually troll for hours and still be able to start the engine.     Before upgrading my Black Max to a 50 amp alternator, I used the 16 amp charging system for years - with a big 24 volt MinnKota trolling motor - and never had a time when there was not enough juice to start the engine.  But I would see battery voltage at 10.5-11 volts from time to time - and the with the demand from electronics and livewell pump I put the alternator kit on my Christmas list 2 years ago   :santa:  I always carry a jumper box in the console just in case - but have never had to use it.  

I still think your high speed situation sounds like lack of fuel - have you tried having someone pump the primer bulb while you run a higher speed?  If that solves it, you almost certainly have a fuel pump or air leak problem.

[LiquidTherapy]

Ok well boat still no bueno! Fuel pump built with new check valves. Runs all day at idle to 2000 to 2500 rpm. WOT for about 30 sec. I was solo again today. So I cant pump bulb while throttle WOT. I did leave it about 1/3 while bogging, jumped back and squeezed bulb. Bulb was firm, very little fuel went threw. Not change in motor, if fact it stalled. I did choke it to get it back runnung. Same thing all the time, just like fuel bowls run dry and SLOWLY looses RPM.

Still wondering as when I pump bulb with fuel line disconnected from top carb. It is hard to pump fuel throw the pump. Squeeze the bulb and slowly fuel goes through pump and out the line going to top carb. Is it suppose to be that hard to pump?

Another thing is the Oil Alrm Module is still hooked up to power pack. Motor is premixed. I know yamahas and prob others will limit rpm when oil alarm goes off. Good idea to remove right? This is the module that sits ontop of number 2 cylinder correct?

I am starting to believe that it is electrical due to it being so consitant. Idle, WOT, boat planes ease back throttle to cruze. Starts loosing RPM. Pull back throttle to just above idle. Rinse and repeat!

Dang, Ok the module I was talking about was the idle module. Has three wires white/black, red and black. Back to the drawing board....

[RickK]

Here is a dumb question - did you replace the bulb?  It might be malfunctioning and not letting the fuel through.  Won't be the first time that has happened.

[LiquidTherapy]

Yes to the dumb question(which is not dumb) the tank was replaced around a year ago, with main fuel line. Goes to a spn on filter then bulb then fuel connector. All new lines from spin on all the way to carbs.

[RickK]

Could have a sticky ball in the bulb?  Do you have access to a free standing tank that you can put in the boat to fuel the boat temporarily - that will point you one way or the other.

[LiquidTherapy]

I do have a extra 6 gallon tank. I am pretty sure fuel is good to motor. There is a inline filter after the bulb that is clear and stays full all the time. Only time it is empty or almost empty is when boat sits for 4 or so days.

Looking at the aftermarket manual I have the Idle module that I thought was on the back of the motor shows to be over the air box/carbs. I do not have this. I see where the oil module was mounted on port side of motor(2,4,6 cylinder bank)side. But what is the module on the top side of the port side? And yes I guess Im going to have to buy a 100 buck factory manual. Anyone have a cheap one laying around?

[redemn93]

did you gut the antisiphon valve before installing the tank?  can you get to it to see if its clogged?