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Mercruiser 250 CID 165hp straight 6 problem
I am having an intermitent problem with this engine in my boat.
When I run at around 2500-3000 rpm and do some modest "wave hopping" in Southern Georgian Bay, occassionally my engine just "dies" (stalls). When I restart it and give it some throttle, it behaves like it is either "fuel starved" or being "flooded". Usually, the "fix" involves stopping the engine, opening the engine cover and pumping the fuel bulb until line pressure is restored, then restarting the engine and running up to 2000 rpm @ idle, THEN re-engaging the transmission (which usually behaves normally then). My mechanic cannot figure it out (without much expensive "diagnosing"). Besides, being the height of the season, I am likely to have to wait till mid-september before he could run up my bill. Any ideas? Bill Toronto, Canada |
alfred pettersen wrote:
I am having an intermitent problem with this engine in my boat. When I run at around 2500-3000 rpm and do some modest "wave hopping" in Southern Georgian Bay, occassionally my engine just "dies" (stalls). When I restart it and give it some throttle, it behaves like it is either "fuel starved" or being "flooded". Gotta figure out which one. It sounds like a fuel bowl level/float valve problem, maybe in combination with a weak fuel pump and/or vapor lock. Are you running your bilge blower? Usually, the "fix" involves stopping the engine, opening the engine cover and pumping the fuel bulb until line pressure is restored, I have never seen a primer bulb on a Mercruiser - how did that get there? This may be part of the problem... you may be sucking air into the fuel sytem at the clamps, or the check valves are sticking or broken... the bulb being there at all may be a sign of a previous problem... Rob |
This is an outboard, right? Have you serviced your fuel filter lately? Has
any fuel system work been done recently? Is your fuel tank built in? If so, perhaps some condensate has accumulated in the bottom and needs removal. If a portable tank have you tried completely emptying the tank to ensure no water is present? When did you last replace the primer bulb and or rubber fuel hoses? Over time these parts can become pretty soft and will suck air. Sounds to me as though you are getting a dose of water in your carb(s) at a particular trim angle when barely on plane, ie. a steep trim angle. Thus the mention of fuel in the tank. Good luck with the problem. Butch "trainfan1" wrote in message ... alfred pettersen wrote: I am having an intermitent problem with this engine in my boat. When I run at around 2500-3000 rpm and do some modest "wave hopping" in Southern Georgian Bay, occassionally my engine just "dies" (stalls). When I restart it and give it some throttle, it behaves like it is either "fuel starved" or being "flooded". Gotta figure out which one. It sounds like a fuel bowl level/float valve problem, maybe in combination with a weak fuel pump and/or vapor lock. Are you running your bilge blower? Usually, the "fix" involves stopping the engine, opening the engine cover and pumping the fuel bulb until line pressure is restored, I have never seen a primer bulb on a Mercruiser - how did that get there? This may be part of the problem... you may be sucking air into the fuel sytem at the clamps, or the check valves are sticking or broken... the bulb being there at all may be a sign of a previous problem... Rob |
Butch Davis wrote:
This is an outboard, right? A 250 Cubic Inch 165 hp outboard by Mercruiser? No... this is an I/O with a Chevrolet-based I-6 engine... which is why I question the "pumping the fuel bulb" part of the problem... Have you serviced your fuel filter lately? Has any fuel system work been done recently? Is your fuel tank built in? If so, perhaps some condensate has accumulated in the bottom and needs removal. If a portable tank have you tried completely emptying the tank to ensure no water is present? When did you last replace the primer bulb and or rubber fuel hoses? Over time these parts can become pretty soft and will suck air. Sounds to me as though you are getting a dose of water in your carb(s) at a particular trim angle when barely on plane, ie. a steep trim angle. 2500-3000 rpm is moving at a pretty good clip with this engine, full-on plane. Rob the mention of fuel in the tank. Good luck with the problem. Butch "trainfan1" wrote in message ... alfred pettersen wrote: I am having an intermitent problem with this engine in my boat. When I run at around 2500-3000 rpm and do some modest "wave hopping" in Southern Georgian Bay, occassionally my engine just "dies" (stalls). When I restart it and give it some throttle, it behaves like it is either "fuel starved" or being "flooded". Gotta figure out which one. It sounds like a fuel bowl level/float valve problem, maybe in combination with a weak fuel pump and/or vapor lock. Are you running your bilge blower? Usually, the "fix" involves stopping the engine, opening the engine cover and pumping the fuel bulb until line pressure is restored, I have never seen a primer bulb on a Mercruiser - how did that get there? This may be part of the problem... you may be sucking air into the fuel sytem at the clamps, or the check valves are sticking or broken... the bulb being there at all may be a sign of a previous problem... Rob |
Never heard of a primer bulb on this engine either. As to 3000 rpm, this
engines top end is 3800 if I remember correctly. Gordon "trainfan1" wrote in message ... Butch Davis wrote: This is an outboard, right? A 250 Cubic Inch 165 hp outboard by Mercruiser? No... this is an I/O with a Chevrolet-based I-6 engine... which is why I question the "pumping the fuel bulb" part of the problem... Have you serviced your fuel filter lately? Has any fuel system work been done recently? Is your fuel tank built in? If so, perhaps some condensate has accumulated in the bottom and needs removal. If a portable tank have you tried completely emptying the tank to ensure no water is present? When did you last replace the primer bulb and or rubber fuel hoses? Over time these parts can become pretty soft and will suck air. Sounds to me as though you are getting a dose of water in your carb(s) at a particular trim angle when barely on plane, ie. a steep trim angle. 2500-3000 rpm is moving at a pretty good clip with this engine, full-on plane. Rob the mention of fuel in the tank. Good luck with the problem. Butch "trainfan1" wrote in message ... alfred pettersen wrote: I am having an intermitent problem with this engine in my boat. When I run at around 2500-3000 rpm and do some modest "wave hopping" in Southern Georgian Bay, occassionally my engine just "dies" (stalls). When I restart it and give it some throttle, it behaves like it is either "fuel starved" or being "flooded". Gotta figure out which one. It sounds like a fuel bowl level/float valve problem, maybe in combination with a weak fuel pump and/or vapor lock. Are you running your bilge blower? Usually, the "fix" involves stopping the engine, opening the engine cover and pumping the fuel bulb until line pressure is restored, I have never seen a primer bulb on a Mercruiser - how did that get there? This may be part of the problem... you may be sucking air into the fuel sytem at the clamps, or the check valves are sticking or broken... the bulb being there at all may be a sign of a previous problem... Rob |
Sorry, missed the part about the CID. The bulb took over my brain. At any
rate, I continue to think of water in the tank as a strong possibility but other things could also be causing the problem. If the engine fuel pump is functioning properly I'd lose the bulb. BUT, if there is water in the tank the bulb could be a way to pump it out. Did you say the fuel filter/water separator can has been checked for water and there was none? Strange problem. Everything I think of is shot down by the narrow RPM range at which the problem manifests. If you are wave hopping any sediment in the tank bottom would be stirred up and enter the fuel suction but the filter should catch it.??? You might want to check the carb and intake mounting and gaskets and retorque the nuts and screws. It might also help to run a couple of cans of carb cleaner through the system. Wish I had more to offer. Butch "Gordon" wrote in message ... Never heard of a primer bulb on this engine either. As to 3000 rpm, this engines top end is 3800 if I remember correctly. Gordon "trainfan1" wrote in message ... Butch Davis wrote: This is an outboard, right? A 250 Cubic Inch 165 hp outboard by Mercruiser? No... this is an I/O with a Chevrolet-based I-6 engine... which is why I question the "pumping the fuel bulb" part of the problem... Have you serviced your fuel filter lately? Has any fuel system work been done recently? Is your fuel tank built in? If so, perhaps some condensate has accumulated in the bottom and needs removal. If a portable tank have you tried completely emptying the tank to ensure no water is present? When did you last replace the primer bulb and or rubber fuel hoses? Over time these parts can become pretty soft and will suck air. Sounds to me as though you are getting a dose of water in your carb(s) at a particular trim angle when barely on plane, ie. a steep trim angle. 2500-3000 rpm is moving at a pretty good clip with this engine, full-on plane. Rob the mention of fuel in the tank. Good luck with the problem. Butch "trainfan1" wrote in message ... alfred pettersen wrote: I am having an intermitent problem with this engine in my boat. When I run at around 2500-3000 rpm and do some modest "wave hopping" in Southern Georgian Bay, occassionally my engine just "dies" (stalls). When I restart it and give it some throttle, it behaves like it is either "fuel starved" or being "flooded". Gotta figure out which one. It sounds like a fuel bowl level/float valve problem, maybe in combination with a weak fuel pump and/or vapor lock. Are you running your bilge blower? Usually, the "fix" involves stopping the engine, opening the engine cover and pumping the fuel bulb until line pressure is restored, I have never seen a primer bulb on a Mercruiser - how did that get there? This may be part of the problem... you may be sucking air into the fuel sytem at the clamps, or the check valves are sticking or broken... the bulb being there at all may be a sign of a previous problem... Rob |
trainfan1 wrote:
Butch Davis wrote: This is an outboard, right? A 250 Cubic Inch 165 hp outboard by Mercruiser? No... this is an I/O with a Chevrolet-based I-6 engine... which is why I question the "pumping the fuel bulb" part of the problem... This has to be right. Out first boat had a 165 hp Mercrusier io. (1970 trihull) The thing had more pulling power than a tractor. That 250cid block would make one tall outboard :-) I am confused by the primer bulb comment as well.. Capt Jack R.. |
The previous owner installed a second 18 US gallon fuel tank and added a
bulb for each tank to prime the line when he switched tanks. When I switch between tanks and don't prime the line with the bulb, it takes forever for the fuel pump to pump from the other tank and I use a lot of battery getting the engine started. Seems the problem actually originates with a "loose spring" in the carb, according to my mechanic. Hitting a good size wave basically knocks the choke partially closed and the engine sucks to choke closed the rest of the way. I discovered this weekend that the way to remedy the situation is before attempting to restart the engine, I put the shifter in neutral and move the lever forwards a couple of times, then put the lever back where the button releases and it is ready to put in gear. I restart the engine and voila, no more hard idling, etc. Seems that priming the engine with the shift lever in neutral resets the choke and I am "off to the races". Short of a complete carb overhaul to change out a somewhat tired old spring (that works 99 % of the time), all I have to do to prevent this condition is take greater care when approaching another boat's wake. Hitting it head on and launching my boat over the wake is the principle cause of this engine condition, but taking the wake at a more progressive angle eliminates the hard jarring the choke gets and prevents the choke closing. I might rebuild the carb next year, not sure. Thanks for all the hints. Regards Bill/Cdnviking "Jack Redington" wrote in message nk.net... trainfan1 wrote: Butch Davis wrote: This is an outboard, right? A 250 Cubic Inch 165 hp outboard by Mercruiser? No... this is an I/O with a Chevrolet-based I-6 engine... which is why I question the "pumping the fuel bulb" part of the problem... This has to be right. Out first boat had a 165 hp Mercrusier io. (1970 trihull) The thing had more pulling power than a tractor. That 250cid block would make one tall outboard :-) I am confused by the primer bulb comment as well.. Capt Jack R.. |
Mercruiser 250 CID 165hp straight 6 problem
Just got 78 galaxy boat with 165 merc cruiser i know its a fuel issue boat was running fine then shut down but mine has pump bulb in fuel line to fuel pump sems to be working fine i can open throttle couple of times it will start then die checked fuel water seperator no water found think could b sucking air im a good mechanic but this my first marine set up i was hoping to get some feed back on known fuel issues on this 165
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Mercruiser 250 CID 165hp straight 6 problem
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