Hi Guys,
Summary of this long post:
I have an issue that I would like some help in debugging my 1994 Chaparral Sunesta with a Merc 5.0L. I have some experience with basic maintenance of engines and machines, such as changing fluids, spark plugs, thermostats, etc., but not much diagnosis experience when things are "off".
The issue was first experienced earlier this year. I bought the boat last year in August, and it started and ran beautifully all of last year. I winterized the system myself, and changed the oil, filters, thermostat, impeller, lower unit fluid at that time. I always ran with marine sta-bil in the fuel and stored with about 3/4 of a tank and a winter dose of sta-bil.
The boat starts easily on muffs. It starts nearly immediately (maybe a crank) when I turn the key. However, when I get the boat on the water, it is more difficult to start. My method is the same as was taught to me last year; I pump full throttle in neutral 2-3 times and then put the throttle at the 1/3ish starting position. When I try to start the boat that way, it cranks over well (doesn't seem to be difficult to turn over) but doesn't fire. I get no sputtering or anything. The first time this happened, I tried for about 3-4 ~5 seconds of cranking (with small breaks and pumping between) before it finally started. I assumed that maybe I had old fuel in the carb or something, I ran the boat for a while at varying throttles, and a lot of full throttle, before stopping to go fishing. When I attempted to restart the boat, it did the same thing as before, but was even more reluctant to fire (I first tried without pumping the throttle, as the engine was warm). I removed the flame arrestor and looked in the carb, and I saw fuel spray when I applied the throttle. I only got the boat to start by applying full throttle. Even then, it took a lot of turning over before it fired.
Being busy with work, I took the boat in to have a tune-up and have them look at it. They changed the spark plugs, cap, and rotor and checked timing. They said that nothing looked bad, and when they took it out, it started fine. When I took the boat out the next time, it started up great the first time. Again, I drove around for a while and then stopped. When I went to restart the boat, I had to again apply full throttle and it finally fired up (this happened 2 more times this outing). When I drive the boat, I notice nothing that seems out of whack; it has plenty of get up and go and runs without hesitation at any speed or any acceleration level.
I have lived with this for a little while, but want to fix it to relieve the frustration. Any thoughts of where to look would be greatly appreciated.
Thanks for any help!
-Austen
Summary of this long post:
- Bought 1994 Sunesta with Merc 5.0L last August
- Boat started and ran great rest of 2011
- In 2012, engine will turn over easily, but does not fire. Eventually it will fire if I keep a constant full throttle applied.
- Had spark plugs, caps, rotor changed, and timing set and same behavior. Only starts when I crank for a while at full throttle.
- Once running, boat has no hesitation, accelerates quickly, runs at any speed, idles well, etc.
- HELP!
I have an issue that I would like some help in debugging my 1994 Chaparral Sunesta with a Merc 5.0L. I have some experience with basic maintenance of engines and machines, such as changing fluids, spark plugs, thermostats, etc., but not much diagnosis experience when things are "off".
The issue was first experienced earlier this year. I bought the boat last year in August, and it started and ran beautifully all of last year. I winterized the system myself, and changed the oil, filters, thermostat, impeller, lower unit fluid at that time. I always ran with marine sta-bil in the fuel and stored with about 3/4 of a tank and a winter dose of sta-bil.
The boat starts easily on muffs. It starts nearly immediately (maybe a crank) when I turn the key. However, when I get the boat on the water, it is more difficult to start. My method is the same as was taught to me last year; I pump full throttle in neutral 2-3 times and then put the throttle at the 1/3ish starting position. When I try to start the boat that way, it cranks over well (doesn't seem to be difficult to turn over) but doesn't fire. I get no sputtering or anything. The first time this happened, I tried for about 3-4 ~5 seconds of cranking (with small breaks and pumping between) before it finally started. I assumed that maybe I had old fuel in the carb or something, I ran the boat for a while at varying throttles, and a lot of full throttle, before stopping to go fishing. When I attempted to restart the boat, it did the same thing as before, but was even more reluctant to fire (I first tried without pumping the throttle, as the engine was warm). I removed the flame arrestor and looked in the carb, and I saw fuel spray when I applied the throttle. I only got the boat to start by applying full throttle. Even then, it took a lot of turning over before it fired.
Being busy with work, I took the boat in to have a tune-up and have them look at it. They changed the spark plugs, cap, and rotor and checked timing. They said that nothing looked bad, and when they took it out, it started fine. When I took the boat out the next time, it started up great the first time. Again, I drove around for a while and then stopped. When I went to restart the boat, I had to again apply full throttle and it finally fired up (this happened 2 more times this outing). When I drive the boat, I notice nothing that seems out of whack; it has plenty of get up and go and runs without hesitation at any speed or any acceleration level.
I have lived with this for a little while, but want to fix it to relieve the frustration. Any thoughts of where to look would be greatly appreciated.
Thanks for any help!
-Austen