Hi guys, I am new to the forum and fairly new to engine work, so do not expect me to understand all technical terms. Also English is not my first language.
My engine is a 2008 Mariner 40 HP 2-stroke 2 cylinder (Belgium version) S/N 0P550276. I bought it six months ago and tested it in a barrel and it ran like a dream on the 3rd pull. When I opened the throttle, it would always take a second or two for the engine to catch up and increase rpm. I payed no attention to this. After some weeks' use it began to die immediately when I put it in idle. Since I could always start it again in fast idle, I ignored the problem and just sailed up to the dock at lowest possible rpm and then let it die. Later it came to the point where it would die even in high rpm after a few minutes or less and also be difficult to start again. While I have been gone on vacation, my buddy worked on the engine, and at one point, he could not get it started at all. As it turned out, he swapped around the spark plug caps... Now I am back, and yesterday it ran for the first time in a month. It ran for about 6 minutes at max throttle before rpm went down over a few seconds and it died. I could start it once, run it for 30 seconds at less than max throttle and then I was not able to start it again. Luckily I had stayed close to the dock since I knew it was a risk.
Here is what has been done so far over the course of the last two months:
- Rebuilt water pump with new impeller and gaskets. At one point I had no cooling water coming out, and it turned out my impeller had a broken arm.
- New spark plugs. I probably didn't even need them.
- "New" used CDM modules and terminals for spark plugs. A local amateur mechanic advised my buddy to get these or gave them to him or something. I tested the old ones, they work just fine and their connectors are not corroded as are the "new" ones. I might just switch back to the old ones.
- New primer bulb. The old one was busted.
- Rebuilt fuel pump with new gaskets and diaphragms. The smaller of the two springs and its plastic cap pushing against the diaphragm was missing completely. I do not understand how the pump could work without it. I cannot confirm if my buddy took it apart and forgot to reinstall those parts.
- New fuel hose and bulb for external gas tank.
Yesterday, before I finally got the engine started, I took home the carburetor to clean it. When I got it open, there was not a speck of crap anywhere in it. I assume my buddy cleaned it but I cannot get a hold of him to confirm it. I did not even bother to soak the jet or inspect the needle valve. The float seemed to operate smoothly but I cannot find the correct float height for a WME 98 carb anywhere. Anyone able to help on this?
The idle mixture screw was 3 and 1/2 turns out and the throttle plate was not closed in idle. I set the mixture screw to 1 and 1/2 turns out and closed the throttle plate completely and reinstalled the carb. This setting however, would not allow me to start the engine in idle. I have no choke and no fast idle option, but my throttle lever allows me to increase the throttle without putting the engine in gear. Doing this, I got the engine started. Adjusting only the idle mixture screw would not allow me to decrease the throttle to regular idle, so in the end i opened the throttle plate just enough to allow the engine to run in normal idle. I then ran it at higher rpms (still without putting it in gear) for some minutes. After this warm up, I could close the throttle plate again and leave it idling with no problem. I left the idle mixture screw at 1 and 1/2 turns out.
I then took the boat out for a sail and it went like I described above. After rowing the boat back to the dock (with the wind in the back, thank god) I tried to start the engine again. I was frustrated and forgot that the throttle plate setting was different the last time I tried, so I didn't succeed. However, I noticed that the fuel hose from the fuel pump to the filter was a little too short causing it to bend sharply right at the fitting on the pump. I cut and installed a new piece of hose. By this time I was worn out for the day and when a few pulls on the cord did not start the engine, I went home. When the downpour wears off, I will give it another go. Not sure if it will be today.
Could the bent fuel hose really be the problem if the carb bowl holds enough fuel to run for those 6 minutes? Why is it then only 30 seconds the second time? And why can I not start it after?
I have not tried changing the fuel for fresh. Do you think this could help?
To me it really looks like a fuel supply problem. All my hoses are securely fitted and I do not have any visible fuel leaks. Could I have an air leak somewhere? Maybe a tiny tear in a hose? I have considered to change all hoses - both the small ones for the primer bulb and the ones in the main fuel supply.
Could the fuel tank be the problem? Can I try putting the bare hose straight in the tank or is there a screen filter that I should not bypass?
Would you recommend to go over the carb once more? I would have loved to install new gaskets right away but they will not arrive for another 2 weeks.
Could it be something other than a fuel issue?
Should I avoid running the engine at high rpms without the propeller in gear?
As for the idle mixture screw on the carb: Can you confirm that screwing it in (clockwise) means leaning the mixture and out richening?
I am based in Greenland, which means two things: 1) the ice free summer season is very short and I would really like to get my engine running soon. 2) spare parts are close to impossible to come across locally and take ages to be shipped.
I know I asked a lot of questions. Any help is very much appreciated!
My engine is a 2008 Mariner 40 HP 2-stroke 2 cylinder (Belgium version) S/N 0P550276. I bought it six months ago and tested it in a barrel and it ran like a dream on the 3rd pull. When I opened the throttle, it would always take a second or two for the engine to catch up and increase rpm. I payed no attention to this. After some weeks' use it began to die immediately when I put it in idle. Since I could always start it again in fast idle, I ignored the problem and just sailed up to the dock at lowest possible rpm and then let it die. Later it came to the point where it would die even in high rpm after a few minutes or less and also be difficult to start again. While I have been gone on vacation, my buddy worked on the engine, and at one point, he could not get it started at all. As it turned out, he swapped around the spark plug caps... Now I am back, and yesterday it ran for the first time in a month. It ran for about 6 minutes at max throttle before rpm went down over a few seconds and it died. I could start it once, run it for 30 seconds at less than max throttle and then I was not able to start it again. Luckily I had stayed close to the dock since I knew it was a risk.
Here is what has been done so far over the course of the last two months:
- Rebuilt water pump with new impeller and gaskets. At one point I had no cooling water coming out, and it turned out my impeller had a broken arm.
- New spark plugs. I probably didn't even need them.
- "New" used CDM modules and terminals for spark plugs. A local amateur mechanic advised my buddy to get these or gave them to him or something. I tested the old ones, they work just fine and their connectors are not corroded as are the "new" ones. I might just switch back to the old ones.
- New primer bulb. The old one was busted.
- Rebuilt fuel pump with new gaskets and diaphragms. The smaller of the two springs and its plastic cap pushing against the diaphragm was missing completely. I do not understand how the pump could work without it. I cannot confirm if my buddy took it apart and forgot to reinstall those parts.
- New fuel hose and bulb for external gas tank.
Yesterday, before I finally got the engine started, I took home the carburetor to clean it. When I got it open, there was not a speck of crap anywhere in it. I assume my buddy cleaned it but I cannot get a hold of him to confirm it. I did not even bother to soak the jet or inspect the needle valve. The float seemed to operate smoothly but I cannot find the correct float height for a WME 98 carb anywhere. Anyone able to help on this?
The idle mixture screw was 3 and 1/2 turns out and the throttle plate was not closed in idle. I set the mixture screw to 1 and 1/2 turns out and closed the throttle plate completely and reinstalled the carb. This setting however, would not allow me to start the engine in idle. I have no choke and no fast idle option, but my throttle lever allows me to increase the throttle without putting the engine in gear. Doing this, I got the engine started. Adjusting only the idle mixture screw would not allow me to decrease the throttle to regular idle, so in the end i opened the throttle plate just enough to allow the engine to run in normal idle. I then ran it at higher rpms (still without putting it in gear) for some minutes. After this warm up, I could close the throttle plate again and leave it idling with no problem. I left the idle mixture screw at 1 and 1/2 turns out.
I then took the boat out for a sail and it went like I described above. After rowing the boat back to the dock (with the wind in the back, thank god) I tried to start the engine again. I was frustrated and forgot that the throttle plate setting was different the last time I tried, so I didn't succeed. However, I noticed that the fuel hose from the fuel pump to the filter was a little too short causing it to bend sharply right at the fitting on the pump. I cut and installed a new piece of hose. By this time I was worn out for the day and when a few pulls on the cord did not start the engine, I went home. When the downpour wears off, I will give it another go. Not sure if it will be today.
Could the bent fuel hose really be the problem if the carb bowl holds enough fuel to run for those 6 minutes? Why is it then only 30 seconds the second time? And why can I not start it after?
I have not tried changing the fuel for fresh. Do you think this could help?
To me it really looks like a fuel supply problem. All my hoses are securely fitted and I do not have any visible fuel leaks. Could I have an air leak somewhere? Maybe a tiny tear in a hose? I have considered to change all hoses - both the small ones for the primer bulb and the ones in the main fuel supply.
Could the fuel tank be the problem? Can I try putting the bare hose straight in the tank or is there a screen filter that I should not bypass?
Would you recommend to go over the carb once more? I would have loved to install new gaskets right away but they will not arrive for another 2 weeks.
Could it be something other than a fuel issue?
Should I avoid running the engine at high rpms without the propeller in gear?
As for the idle mixture screw on the carb: Can you confirm that screwing it in (clockwise) means leaning the mixture and out richening?
I am based in Greenland, which means two things: 1) the ice free summer season is very short and I would really like to get my engine running soon. 2) spare parts are close to impossible to come across locally and take ages to be shipped.
I know I asked a lot of questions. Any help is very much appreciated!