2008 50hp two stroke issues

[nuffsaid]

I have just finished my 3rd outing with my new to me boat and 50hp two stroke and I have a couple of questions. First issue is that while trolling at an idle, the engine will keep dying unless I pump the primer bulb every few minutes. There is no issue with fueling at increased rpms. This was at a lake that is 6200 ft in elevation. I wonder if the high altitude could cause lower than normal vacuum and thus affect the fuel pump. Any thoughts?

The next issue involves the water pump stream. At idle there is only a dribble of water coming out, I felt the water and it is not hot. As I increase rpms, there is a better stream, but there doesn't seem to be much pressure behind it. Is this normal or should I take a look at the impeller? How do I access the impeller on this motor? I don't have a manual yet, so I am looking for a guideline. I am a mechanic by trade.

 

[goombadi99]

Re: 2008 50hp two stroke issues

I have a 2004 50 horse. I just replaced my impellar about 2 weeks ago because I was having this same issue. Even with a new impellar, my stream isnt very strong at idle. I do how ever have a steady stream at idle just doesnt look strong. But after being in the lake today with the boat for 3 hours, everything was fine.
As for the impellar, mine only took about 20min from start to finish.
Trim the engine up, on the lower half of the lower unit on the side facicng the transom you will see the shifter linkage, its a ten mil rod, losen the jam nut on the bottom of this rod. Once loose you can unthread the top off. Now the shifter linkage is disconnected.
remopve the 4 lower unit bolts,16mm. on the top of the anoid there is a plastic cap, remove the cap to gain acces to the anoid bolt and remove anoid. Once this is removed you will see the 5th hidden bolt on the lower unit, remove this bolt and lightly wiggle the lower unit off. Once off you will see the long shft that the impellar rides on, it is held on by 4- 10mm bolts, remove these bolts and slide housing off to expose the impellar and replace as ness. hope this onfo helps.

 

[nuffsaid]

Re: 2008 50hp two stroke issues

thanks for the reply, one other question, I was running in a lake that was only 42 degrees. Does cold water have an effect on how much water flows through the tell tale?

 

[goombadi99]

Re: 2008 50hp two stroke issues

no it will not have an effect at that temp. one thing i have learned about these smaller hp engines is that that they dont produce a stream like the bigger disp engines. what king of boat is this set up on and what top speed are you seeing out of your boat?

 

[nuffsaid]

Re: 2008 50hp two stroke issues

This motor is sitting on a Lowe fm 165, it has a 15 pitch prop, which is way too much prop for my altitude. I was able to get 25.5 mph at only 4200 rpms wot with just me in the boat yesterday and last weekend, with my wife and I, at a slightly lower elevation lake, I could get 24 mph at 4500 wot. I was hoping my new prop would have been here to try, but it will probably show up on Monday. It is an 11 pitch, I am setting the boat up for high elevation and heavy loads. Hopefully it will do 25 plus with the 11 pitch @ wot.

 

[goombadi99]

Re: 2008 50hp two stroke issues

you should be running closer to 5200-5600rpms @WOT on that , those rpm numbers seem pretty low, thats more of a cruising speed rpm

 

[nuffsaid]

Re: 2008 50hp two stroke issues

Well, I dropped the lower unit and checked the water pump, it looked perfect, the wear plate also looked perfect. I kind of wonder if the plastic sleeve that connects the water pump housing to the copper tube wasn't seated enough. I seated it fully on the water pump housing before installing it. Hope that takes care of it. Blew air through the pee hole and it felt clear. We shall see. At least every bit of this motor looks the way that I thought it would be when I bought it. It looks brand new.

 

[goombadi99]

Re: 2008 50hp two stroke issues

when you decide to test it dont use muffs, use a large pal. when i hooked the muffs up it would barely come out of the weep hole, but once i put it in the pal it had a nice stream to it. did you make sure that the key way was back in when you slid the impellar back down? and also the is 2 plastic washers one on each side of the implellar that you need to make sure stay lined up.

 

[verado7]

Re: 2008 50hp two stroke issues

your dieing at idle issue is likely a bad primer bulb - check valve letting gas run back into tank - i'd change that first - before doing the fuel pump .

 

[nuffsaid]

Re: 2008 50hp two stroke issues

Thanks for the reply on the primer bulb. Is there a good way to test the primer bulb check valve? Could I take it off and fill the out put side with gas and see if it holds?

When I replaced the water pump impeller, I made sure the key was properly installed, that was after I found it on the floor because it fell out and I didn't see it fall. I will find a garbage can to test it in tomorrow to see if the problem is fixed.

 

[nuffsaid]

Re: 2008 50hp two stroke issues

goombadi99,

I was just reading some other posts and I saw mention of a seal that goes on the water tube coupler. The coupler on my motor has a seal that goes to the copper tube, but the bottom part that goes over the water pump outlet has some groves on the inside of it but no seal. Is this right or is it missing a seal?

 

[verado7]

Re: 2008 50hp two stroke issues

you could remove the bulb and blow air thru it - but - i would just replace it - not uncommon for even a new one to fail quickly .

 

[nuffsaid]

Re: 2008 50hp two stroke issues

If the bulb has failed, would it not be able to get it to pump up hard? Or, do you think it might just be leaking slightly allowing fuel to drain back slowly?

 

[nuffsaid]

Re: 2008 50hp two stroke issues

I started the motor a tank this afternoon and right off the bat I have an excellent flow of water from the tell tale, it shoots 5 feet! I ran the motor for around 30 minutes and it never stumbled or died once, just sounded perfect. So what would make the difference in fueling between my house at 4200 ft and the lake at 6200 ft?

 

[verado7]

Re: 2008 50hp two stroke issues

less oxygen at 6200 feet sounds like you have a lean condition at lower altitudes

 

[nuffsaid]

Re: 2008 50hp two stroke issues

typically when going up in elevation, the mixture gets richer. But it is not acting like it is out of sinc. After running the engine yesterday for over a half hour and it not cutting out even once, there has to be something to do with the fuel pump not putting out enough volume at idle at higher elevations. Maybe now that I got my 11 pitch prop, the engine won't be loaded as much at idle and the issue might go away. We will see. At least the tell tale is squirting a solid stream 4 feet long at idle.

 

[verado7]

Re: 2008 50hp two stroke issues

yes -less oxygen at higher altitude will give you a richer mix - thus at lower altitudes you have more oxygen so the mixture will be leaner .

 

[nuffsaid]

Re: 2008 50hp two stroke issues

I ran my boat today with my new 11 P prop and all my issues are gone. The tell tale is providing a nice steady stream, the engine never died once while trolling and the new prop made it easy to troll at a good speed and it got up on plane much faster and top speed is also better. Top that off with 6 18 inch trout in the boat and headed to the smoker and I am very happy