First....thanks for all the responses on "2gm stalling". For the record, I had a combination of bad fuel and I cleaned the gas tank pick up tube screen. My problem now is that I cannot get good power while in gear. I can get full rpm's in neutral but once I put the boat in gear, I can only get about 2000 rpm. Black smoke occurs also. The prop and bottom are clean. Any suggestions?
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Mixing elbow is next.
Chris: Have you checked the mixing elbow. I posted an article on this in the photo forum. Take a look at yours and see. If you cannot get enough exhaust through the system you will not be able to get the RPM's up where they should be. Black smoke is an indication of overloading the engine. Assuming that the elbow is not your problem, you need to check your prop pitch too.
Chris: Have you checked the mixing elbow. I posted an article on this in the photo forum. Take a look at yours and see. If you cannot get enough exhaust through the system you will not be able to get the RPM's up where they should be. Black smoke is an indication of overloading the engine. Assuming that the elbow is not your problem, you need to check your prop pitch too.
D
Doug
In addition to Steve Dixon's post...
The best way to check and clean mixing elbo for 2gm. Take off the hose that connects header tank (aka heat exchanger) to the mixing elbo. Then take off both fittings. Note the hose fitting (90 degree) that is affixed to the header tank is not pipe threaded, there is a small set screw below it and it needs to come out first. then just twist and pull the elbo out. It is an o-ring sealed fitting. The fitting on the elbo is a pipe threaded type. Turn that out carefully and check for carbon coking. Use a small blade scredriver, hanger, etc. and be careful of the threads. If pretty bad you may need to run a pipe thread tap in the threads anyway before replacing fitting. the fitting screws into a port inside of the mixing elbo that goes up and over the bend to the exhaust hose side. Taking the exhaust mixing elbo off should not be needed if you do it this way (and believe me, you dont want to try to take it off either!). The header tank side: Stick your finger in hole to feel for clogging. A flashlight and small dentist type mirror is great too! Run engine and mid idle and watch water from exhaust thru-hull. should surge but should be copious. I will say that lack of rpm range sounds more like over pitched prop...is it new? Good luck! Doug
The best way to check and clean mixing elbo for 2gm. Take off the hose that connects header tank (aka heat exchanger) to the mixing elbo. Then take off both fittings. Note the hose fitting (90 degree) that is affixed to the header tank is not pipe threaded, there is a small set screw below it and it needs to come out first. then just twist and pull the elbo out. It is an o-ring sealed fitting. The fitting on the elbo is a pipe threaded type. Turn that out carefully and check for carbon coking. Use a small blade scredriver, hanger, etc. and be careful of the threads. If pretty bad you may need to run a pipe thread tap in the threads anyway before replacing fitting. the fitting screws into a port inside of the mixing elbo that goes up and over the bend to the exhaust hose side. Taking the exhaust mixing elbo off should not be needed if you do it this way (and believe me, you dont want to try to take it off either!). The header tank side: Stick your finger in hole to feel for clogging. A flashlight and small dentist type mirror is great too! Run engine and mid idle and watch water from exhaust thru-hull. should surge but should be copious. I will say that lack of rpm range sounds more like over pitched prop...is it new? Good luck! Doug
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Jim McCue
power loss
I had power loss on my SAAB, could get more than 2000 rpm before power plateau-ed out.. Turned out my exhaust pipe was gummed up and clogged with muffler liner material that dislodged from the walls of the ,uffler and choked the thru-put. I'd check your mixin elbow! J. McCue
I had power loss on my SAAB, could get more than 2000 rpm before power plateau-ed out.. Turned out my exhaust pipe was gummed up and clogged with muffler liner material that dislodged from the walls of the ,uffler and choked the thru-put. I'd check your mixin elbow! J. McCue
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Harry Asbury
Mixing elbow??
I'm just wondering, if the mixing elbow is fouled, blocking the exhaust flow and keeping the rpm down due to back pressure, and that sounds correct - why would the engine make full rpm in neutral when it would be sucking, burning, exhausting max cfm's? Yet be choked down when in gear. Sounds more like drag somewhere. Maybe in the shaft/stuffing box?
I'm just wondering, if the mixing elbow is fouled, blocking the exhaust flow and keeping the rpm down due to back pressure, and that sounds correct - why would the engine make full rpm in neutral when it would be sucking, burning, exhausting max cfm's? Yet be choked down when in gear. Sounds more like drag somewhere. Maybe in the shaft/stuffing box?
S
Stevec
I've had the mixing elbow problem and...
if I remember corectly, you can't get the RPM's either in gear OR neutral...If the symptoms are correct there must be a different problem. Are you absolulely sure that you are still not having fuel starvation problems...
if I remember corectly, you can't get the RPM's either in gear OR neutral...If the symptoms are correct there must be a different problem. Are you absolulely sure that you are still not having fuel starvation problems...
L
Les
Just a Thought
Chris, Before last weekend my first guess would have been the mixing elbow. However sometimes its better to read and follow what the the book says. Two weekends ago we took a trip across the bay. The engine would run fine at 2500-2700 rpm for about 45 -60 mins then emint lots smoke. No overheat lite, no loss of exhaust water and the smoke quit by reducing the rpm to 1500 for a few minutes. The engine ran fine at 2000-2300 for the weekend but if I went over 2500 the same thing happened. After the trip we started the analysis of what happened. The book said dark smoke = check fuel, air, elbow. Then timing, valves etc. The fuel was perfect, no water, sludge or any contaminants evident. The elbow was not clogged. The 1/4 in opening in the brass fitting was perfect with no corrosion. I was at a loss. My wife said (I have to admit this) why don't you check the air filter? Yea, Yea, Looked at the sponge rubber filter and it looked good but a little greasy. Book says to clean use water and detergent. What could that hurt. Put 1/2 gal of warm water in a pail along with good old Joy. Droped the filter in and the clean water almost instantly turned black. The sponge was so dirty it took three pails of soapy water to clean. Probably the original filter and had never been cleaned in 9 years. Engine runs fine now. Lack of air will also cause poor combustion and smoke just like bad fuel or overworking the engine. Word to the wise is check the solutions in order and don't skip. Glad I didn't get to the oint of calling the mechanic to check timing, valves, etc. Les Andersen s/v Mutual Fun
Chris, Before last weekend my first guess would have been the mixing elbow. However sometimes its better to read and follow what the the book says. Two weekends ago we took a trip across the bay. The engine would run fine at 2500-2700 rpm for about 45 -60 mins then emint lots smoke. No overheat lite, no loss of exhaust water and the smoke quit by reducing the rpm to 1500 for a few minutes. The engine ran fine at 2000-2300 for the weekend but if I went over 2500 the same thing happened. After the trip we started the analysis of what happened. The book said dark smoke = check fuel, air, elbow. Then timing, valves etc. The fuel was perfect, no water, sludge or any contaminants evident. The elbow was not clogged. The 1/4 in opening in the brass fitting was perfect with no corrosion. I was at a loss. My wife said (I have to admit this) why don't you check the air filter? Yea, Yea, Looked at the sponge rubber filter and it looked good but a little greasy. Book says to clean use water and detergent. What could that hurt. Put 1/2 gal of warm water in a pail along with good old Joy. Droped the filter in and the clean water almost instantly turned black. The sponge was so dirty it took three pails of soapy water to clean. Probably the original filter and had never been cleaned in 9 years. Engine runs fine now. Lack of air will also cause poor combustion and smoke just like bad fuel or overworking the engine. Word to the wise is check the solutions in order and don't skip. Glad I didn't get to the oint of calling the mechanic to check timing, valves, etc. Les Andersen s/v Mutual Fun
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