Wierd Engine Problem

[Tequila Dawn]

Took the Grady for its madien voyage Saturday morning out on the lake. Boat started right up, idled well, everything seemed fine. Took it out got past the No Wake buoys and got it right up on plane. Very pleased at this point, holding 4000 rpms the boat rode beautifully. We stoped out on the lake to just sit in the peace and quiet. Then it happened. Tried to refire the motor.. NO LUCK. 20 minutes later she finally fires but wont go above 1500 rpm. Everytime I got her above 1500 she stalled out. Limped back to the ramp and brough her home.

Now I am trying to figure out what happened to cause this problem.

Varieables:
1) New Gas from Lukoil
2) New Quicksilver 2 stroke mix at 50:1

I am thinking plugs but hearing about E10 has me wondering now. I have a 10 gallon fuel tank running straight to the motor which is a 1979 Mariner 80hp.

Any help would be appreciated. Want to be out on the lake for the fireworks this friday.

Thanks In Advance
Jude

 

[plymouthgrady]

engine

once you drove around you shook up everything in the tank (gas and water). Tell tale sign is that it will run at idle but won't run under load. I'd bet you have bad gas. Put on a fuel water seperator and bring lots of extra filters.

 

[Tequila Dawn]

Thanks plymoth. It definatley ran at idle but not under load. I was figuring that it had to be something like that. Besides the seperator do you think a plug change would be inorder?

Now to figure out how to mount the seperator with a small gas tank :roll:

 

[plymouthgrady]

rough running

Did you do a spring tune-up? New plugs, lower gear oil, filter, etc? Check seals & gaskets for weeping?
New plugs never hurt but it sounds like you have other issues other than plugs. Check some of the other posts, there's really good advice on how to tackle gas issues.

 

[CJBROWN]

Hmmm...old motor = carburators? I'll bet you have water sitting in bottom of the bowls if they have them. Once it gets on the main jets it picks up the water.

Do you have jumbo fuel/water seperator fuel filter? I would add one with the racor glass drain bowl.

Clean out the fuel system on the motor. Consider puping out the fuel tank. Maybe you'll find a bunch of water sitting in the bottom.

 

[Tequila Dawn]

Motor is definatley carbed. Its a 1978 :shock:

The fuel system was basically brand new. I used the existing fuel line but the fuell cell I bought last week. The gas and oil mix went in the night before the launching. Oil was brand new off the shelf and gas came from the corner station that also filled my trucks tank at the same time (truck first, cell second) so at least i know the fuel and oil was fresh.

I guess I will try a tune up also. I downloaded the pdf for the motor off the net so I guess I can do it in the driveway. As far as the carbs go I hope a rebuild is not inorder I hate rebuilding carbs.

Thanks for the responses. I will go out and get a fuel/water seperator and also add some dry gas to the cell to remove any existing water. Stupid ethanol :evil:

 

[catch22]

This may sound stupid but... are you sure the fuel tank is vented? An easy way to check, is to losen the fill cap and see if air rushes in. Also, the primer bulb might be callapsed. If the tank is not being vented, the motor might run strong for a while until it starts to pull vacuum on the tank.
Speaking of primer bulbs, was that changed? You could also check for any callapsed, or kinked fuel lines.
Can you run the motor on a different, portable tank?

 

[Tequila Dawn]

catch22 thanks for the info. I didnt even think of the vacume problem. I do know the tank is vented, how well its working I will have to check. The primer bulb was a part I did not replace but am going to later today. I dont have a secondary tank but the one I have is portable. Its just a plain ol' 10 gallon red fuel tank.

Hopefully this afternoon I will be able to get out there and add the seperator, ne line, new primer bulb, some watersorb in the gas, and new plugs.



Im hoping that takes care of the problems. If not then its something else that will take time to track down

 

[timo14]

My guess is Catch22 hit the nail on the head... I've done it several times on my 10hp merc. Can you see in the tank? Any crap on the bottom? Is there an in-line fuel filter on the motor? It may be clogged. With a 10 gallon tank, I assume its a portable, you should be able to look inside pretty easily. You'll see dirt or water if you've got it. Tilt the tank a little to one corner... the water will run to that corner since it's heavier.

 

[Tequila Dawn]

Thanks for the replies guys.

Yesterday I did a plug change, found out the plugs that wer ein there were wrong :x two steps too cold. Also added the water seperator, inline fuel filter and new primer bulb, and added startron (sp) to the fuel itself.

I cranked the motor up and after one sputter, probably from air in the line, she fired right up and ran wonderfully. I put it in gear and no sputter or hesitation. Thursday I will get her in the water to give it a real under load test.

But so far I am very pleased vs what I delt with Saturday.

Thanks for all your help and I will keep you all posted!

Regards,
Jude

 

[Tequila Dawn]

Well it works She ran pretty good over the long weekend. Started and stoped well idled nicely.

On to the next question now.. she doesn't like coming out of the hole I have to s l o w l y walk her up to speed. If i try to gun it or even steadly incrase throttle she stalls out.

Folks around the dock are telling me probably the jets.

I will probably be going for a tune at the local marina but for now was wondering if anyone here has suggestions as to the problem.