motor issues, carbs dirty maybe?
 

so i repowered a few years ago w/ a carbed 150 johnson on my 18 seacraft. had an old mercury 200 racing motor that ran like a scalded dog, but not very often. anyway, went out monday to go catch some breeder reds. ran ten miles, fished for a few hours, and on the way in i started losing power. motor bogged down at about 4000 rpm and would slowly lose power (bucking). i stopped, put it in neutral, let it idle for a few, and started again. got 1/4 mile or so, same deal. repeat, but just barely got her on plane, and went a bit farther before it happened again. this time was accompanied by loud warning beep and "check engine light", which means fuel flow restriction. this happened once before last time i was out (the previous monday), but just once, and i forgot about it. i change plugs and fuel/water separators every six months, but i think it may be time to clean the carbs. is that what this sounds like? would love to tackle it myself, but would love to get some insight first. im no master mechanic, but i can turn a wrench and dont mind getting dirty.

as for gas, i try to run ethanol free, but dont always. use bright blue startron religiously though...

Re: motor issues, carbs dirty maybe?
 

before going after carbsi would try and run it on a differnt fuel tank. this will sperate the problem,boat or motor. if it runs fine then try finding your fuel pick up in the tank.alot of times theres a screen that gets cloged up at the bottom.also check and see if there is a check valve at the tank its self. if it is the motor then yes, i would take the carbs off and clean them. make sure and buy kits before taking them off.the oring and gaskets will swell and will never go back together. good luck!

Re: motor issues, carbs dirty maybe?
 

I'll bet you have water accummulation in the float bowls. take them off and dump them and clean them out. It is probably from water seperation from the gas and it has taken up most of the volume of the bowls, thus limiting the amount of burnable fuel reaching the motor.

Just my 2C. Good luck.

Re: motor issues, carbs dirty maybe?
 

check the anti-siphon valve I had the same problem a few years back and found some trash in the anti-siphon valve it is mounted to the top rear end of the tank where the fuel line connects to the tank. Also check all fuel filters and check fuel lines to make sure the new ethanol gas hasn't struck again.

Re: motor issues, carbs dirty maybe?
 

pulled apart one of the carbs pre-knowledge tonight (very carefully). they were clean as a whistle. factory clean looking. cleaned it anyway, then pulled brass screws in stack and sprayed cleaner in there too. checked fuel filter on front of fuel pump and that is clean too. i have already checked fuel pick up and the anti syphon valve has already been removed. im at a loss. might be another bad vacuum switch, i heard they made a bad batch from my mechanic, maybe the good folks at omc were kind enough to send me a bunk replacement the first time. not sure how that explains the loss of power, although it would explain the godawful beeping. i have an inline filter for fuel management (which i dont use) that i may remove and see if that does it. blew off work to catch fish monday, and now im paying for it w/ a crazy week. going to try and water test thursday maybe, any more insight prior to that would be much appreciated.

Re: motor issues, carbs dirty maybe?
 

Hmmmm, maybe overheating?

Re: motor issues, carbs dirty maybe?
 

If you got a continuous warning tone and not beeping it could be the overheat alarm. Have you changed your water pump recently?

Re: motor issues, carbs dirty maybe?
 

Definitely sounds like fuel starvation. When you let it idle for a few minutes, the pump refilled the float bowls, so you were able to get on plane until the fuel level in the bowls dropped. Hope you're not running premix (oil in the gas) instead of oil injection, because when you starve a pre-mix motor of gas, you're also starving it of oil! Have you checked the fuel lines between the pump and carbs? I had one of those lines deteriorate and plug one time on my old V-4. Could also be a weak fuel pump or a leak in the line to the crankcase that feeds the pulsations that drive the fuel pump!

Re: motor issues, carbs dirty maybe?
 

How old is the gas mine did almost the same thing when I got it it ran good on a portable tank but not the main drained the 80 gallons it came with refueled and it's been good

Re: motor issues, carbs dirty maybe?
 

Several good points made. I think Daltonmarine offers a good starting point. I'd start at the beginning of the fuel chain supply chain. Are you running off the main tank or auxiliary portable? Injecting oil or premix?

Assuming the primer bulb is still fully pliable, does it collapse at all when it cuts out? If so, that would likely indicate clogging between the tank and the primer bulb...or even a clogged or closed tank vent.
Here's what I found once that gave the same symptoms (my guess on this is that at some time silicone was used as gasket for sending unit which broke down and sunk to the bottom of tank) obviously no screen on my pick up tube:
http://i261.photobucket.com/albums/i...ckage004-1.jpg

Then check for water in the separation filter. Might just suck some fuel out into a clear container prior to the separator and see how it settles out...

No clogs, no water - work your way up to the fuel pump, fuel lines, then on to carbs... Bushwacker's logic makes a lot of sense if the problem isn't prior to the carbs.

Good luck, keep us posted

Re: motor issues, carbs dirty maybe?
 

If its a 60 degree 150 check the shift assist switch on the lower starboard side attached to the linkage. It kills power to 1 cylinder bank when shifting and will do some strange things to the power pack when going bad. Don't know if the 90 degree motors use them.

Re: motor issues, carbs dirty maybe?
 

this does make the most sense (starving the motor). i checked all the fuel lines from the pick up back last fall (when i replaced vacuum switch), all was good. at that point i replaced primer ball. i always check the fuel in the separator when i change it. this time had some lovely metal flakes, but no water. guess i will recheck fuel lines, add splice in place of fuel management filter, and try to water test. if that fails, motor is still under warranty, and she goes to the shop. the joy of living on the coast is this time of year there is a 2 week wait minimum at all mechanics, even the country guy i use in the middle of nowhere...thanks as usual for all your ideas and suggestions, ill keep you posted.

Re: motor issues, carbs dirty maybe?
 

Year and model of Motah?

The check engine light/horn monitors vacuum for fuel. Get a good long sweep gauge with 20"s max and work your way back to the tank. I had a clogged Racor with maybe 30 hours on it after we got e 10 shoved down our throats. Cleaned out all the crap from my 20 yr. old tank.

I blew the VRO diaphram on my `96 150 last Tues. The kit was 62 clams and took about an hour. Very easy! I run premix.

Cheers,
GFS

Re: motor issues, carbs dirty maybe?
 

motor is an 06 model but i hung it new midsummer 09. im not sure if the vaccum switch is a separate issue from the bogging down or not, like the sweeper idea. ill try it.

think model is jx150psd or something along those lines...

Re: motor issues, carbs dirty maybe?
 

Isolate and Eliminate

start at one end of the system - btw squeezing the bulb will overide the fuel pump to eliminate that

Re: motor issues, carbs dirty maybe?
 

i know, ive limped home using the bulb before...just got some time looking around, removed navman inline fuel gauge, its useless. lines clean to bulb. lines clean from bulb to black pipe where there is a connection somewhere (fuel line from motor meets fuel line running through hull somehow). all lines on motor appear clear, but are held on using crazy connections, dont want to void warranty. hate to say it but she may be heading for the shop. also, noticed a good bit of oil stains on lower unit of motor running down towards the foot. unrelated?

Re: motor issues, carbs dirty maybe?
 

i am going to try the auxiliary motor idea tomorrow. question; can i modify a jerry jug and use a 3/8 ID fuel line (like i have now) as the pick up and a primer bulb to prime it or do i have to go out and buy an expensive one? i asked a few friends if they have one, but havent heard back yet. i guess the fuel pump pulls the gas so it doesnt have to be super pressurized, ill just tie a weight to the end of the fuel line (like an aerator).

Re: motor issues, carbs dirty maybe?
 

Pump the bulb on the pony tank. You have a fuel delivery issue. Do not run big `till solved.

Listen,
GFS

Re: motor issues, carbs dirty maybe?
 

A lot of the 6 gallon tanks were set up for smaller motors (like V-4's) with 5/16 dia. fuel lines. Wouldn't use one of those for a V-6. I think you'd be better off with a jerry jug.

If it acts up again, try pumping the bulb. It's behavior will give you some good clues. If it stays flat after squeezing, there is a restriction up stream, between bulb and fuel supply. If you can't pump it much before it gets hard and motor doesn't pick up speed, there's a restriction between the bulb and carbs. If doesn't get real hard and motor picks up speed, you may have a weak fuel pump or a blockage that pump suction can't overcome but pressure will at least partially overcome. Be careful not to run long in lean condition because lean combustion produces very high temperatures that can either burn a piston, cause it to expand so much that it can score the cylinder or even seize up!

Re: motor issues, carbs dirty maybe?
 

That motor has that interrupt switch. Unplug it and run the motor. Don't shift more than necessary and when you do have to shift, throw it in gear as fast as possible..

Re: motor issues, carbs dirty maybe?
 

interrupt switch? what is that? got 6 gal jerry jug w/ 3/8 fuel line assembly filled w fresh ethanol free gas. trying to get work done to see whats what out on the water...

Re: motor issues, carbs dirty maybe?
 

bushwhacker, was pumping bulb before, it acts the same way as always. doesnt stay fully compressed (lines clean from bulb to carbs). doesnt get too hard either though, but it never has. i am convinced its something in the motor itself, although i am still going to try running fresh clean gas first.

Re: motor issues, carbs dirty maybe?
 

just got back from water test. idled around to purge any old gas, then got up on plane for a few miles, nothing wrong, no beeping, no warning lights, no godawful bucking. i wound up burning about 4 gallons of fresh ethanol gas w/ no issues at all. im going to try and get it pumped tomorrow. may not be the only issue, but its a good start. i dont think i have more than 20 gallons in the tank. thanks for all the good info guys, ill keep you posted.

Re: motor issues, carbs dirty maybe?
 

The bulb is only to prime the system, after that its just a fuel line item, means nothing unless its being sucked flat. Once started and warmed up the motor should run with a fuel line stuck in the lawnmower can - just say'in

Re: motor issues, carbs dirty maybe?
 

pumped out bad fuel today using an $8 hand pump from walmart. it would have been great if it were 2-3 gallons. 20, not so cool. saved all gas to see if there will be water separation. disassembled the entire fuel line assembly from the pickup to motor, blew it out w/ air, checked it for suction, everything good. new gas goes in, and we shall see. we have 37 public boat landings in the tricounty charleston area, and i swear 75% of boats use two of them, one of which is 2 miles from my house; or id go test it right now.

Re: motor issues, carbs dirty maybe?
 

Any chunks of anything turn up in your extraction bucket? Anything in your fuel water separator?

What did you put the old gas in and what will you do with it?

Re: motor issues, carbs dirty maybe?
 

no chunks, havent checked for separation yet. fuel is sitting in one of those grey storage bins, unsure of how to get rid of. any suggestions? my buddy has a landscape company, im trying to pawn in off on him. to be honest, the fuel doesnt look too bad.

Re: motor issues, carbs dirty maybe?
 

Mix that gas into one of your cars. What I did is 10gals of fresh gas with 5 from the tank. My sons explorer went thru 50gals with no problems

Re: motor issues, carbs dirty maybe?
 

Don't do that with a small motor with variable valve timing. Phase separation in the gas causes greater instability in ignition, and can lead to engine detonation even when the engine is tuned properly. That gas will probably be fine run in a simple overhead valve cast-iron motor, but many newer compacts should not run gas with water or phase separation.

I ran my 24 gallons of left-over gas from my recent "ethanol misadventures" through a friend's 1982 full-sized Ford Bronco. We ran it through a Racor water separating filter while pumping it out of my boat, and collected over half a gallon of water. We mixed in 14 gallons of fresh, ethanol-free gas to top off his huge 44 gallon fuel tank. No problems after that running it in his truck.

We had a blast at the mud-hole with that big-ole 460 ci big-block. I even was wearing my black clerical shirt and got spattered with mud. Some people thought that was pretty funny, a mud-spattered old priest ankle-deep in the mud, laughing like a loon. I don't know why. :D :D

Re: motor issues, carbs dirty maybe?
 

ive got a friend w/ an early 80s GMC (bronco equivalent, i forget name) who could run it. my tundra is an 08, and id rather not risk it.

while checking the fuel pickup in the tank, i noticed that it is a 5/16 ID line, while the rest of the fuel lines are 3/8. its a strange design; 90' angle, barb fitting above tank for 3/8 line, barb fitting below threads on the bottom for 5/16 line. the pickup is just a semi rigid tube that was loose. i flipped it around and it is now snug, but cant get a hose clamp on because of threads above barb fitting. may try and replace whole assembly. they didnt have one at lowes or west marine in the fuel fittings section though...

fr. frank, i would pay money to see you in your clerical shirt at a mud pit by the way...

Re: motor issues, carbs dirty maybe?
 

A rubber hose on a barbed fitting w/o a clamp is asking for trouble because there's nothing to keep that hose from coming off in rough seas! I'd change that entire pickup assembly to a solid 3/8 pipe and make sure there is no smaller diameter in any of the elbows or fittings! 5/16" is too small for a V-6 and could cause you to burn a piston at WOT. The dealer that used to service my old V-4 said they had traced repetitive power head failures on a V-6 to that type of restriction - the lines were 3/8 but there was a restriction in a 90 degree elbow! I think the pickup in my OEM tank is a 1/2" diameter pipe! The V-6's on a 20 are more vulnerable to this problem than the V-4's because you have so much power that you're less likely to notice a small drop in power due to a lean cylinder!

Re: motor issues, carbs dirty maybe?
 

thanks bushwhacker, i thought the same thing. just water tested again w/ new ethanol free gas in main tank (w/ 5/16 pickup). ran about 8 miles between 3500-4800 rpm, like a top. hopefully greasy paws and skinned knickles have triumphed this time. im going to pull the fitting and see where i can find a suitable replacement tomorrow probably.

Re: motor issues, carbs dirty maybe?
 

You can get it at the West Marine on N. Rivers in Charleston.

Re: motor issues, carbs dirty maybe?
 

so after all this i think it was just a loose pickup inside the fuel tank. went out today for a cruise w/ the lady friend. covered about 15 miles round trip probably, never faster than 4200 rpm, lots of idling around, not a hiccup. we shall see...

thanks for all the sound advice everybody.

Re: motor issues, carbs dirty maybe?
 

since the motor seems good enough, time to get cracking on that lady friend