Motor cut out at WOT

[steveo32]

Hi, as most know I am new and I just took my boat out today. The launch went well, the motor started up idled for a while and then I started my line around the lake. I planed out pretty quick and was gaining speed nicely. Hit WOT and started to make my turn. Straightened out from the turn and I could feel a loss of power like the motor was starting to cut out so I let off the throttle a little and engine cut out this occured in about 5-10 minutes worth of driving. Took me 20 minutes to get the boat to the side where a resident asked what happened? You were going great and it just died. I aggitated at the time said yeah I know. So I began to drag the boat by the shore and of course it kept getting stuck in the sand. So about 100 ft from the boat launch I was fed up and just got in the water calf deep (temp outside was 44F so water was f ing cold) and started pulling the boat until I got to the boat launch. Spark plugs are wet fouled, they were brand new too. Tried several times to start with no avail. Carbs were flooded. Tried when I got home on the muffs too with no luck. the motor turns over and sounds like it will start but doesn't. Motor is a 1975 70 hp 3 cyl, it had started every time on the muffs before this. Tell tale hole has water coming out wit the muffs. Couldn't see on the lake because the water above tell tale when I would lean over the back to look, I weigh about 215lbs. So what else do I need to check.

Thanks

 

[steveo32]

Re: Motor cut out at WOT

In the morning I will change out the gas and put the old spark plugs back in and see what that does.

Let me know if there is anything else you guys think it may be.

Thanks

 

[HighTrim]

Re: Motor cut out at WOT

Follow this and let us know what you find.

http://forums.iboats.com/showthread.php?t=158071

 

[Yamajoe]

Re: Motor cut out at WOT

Check your compression. should be all 100 and above.

[I let off the throttle a little and engine cut out ..]

You may have a short on your kill switch, which is moving about and grounding, in this circumstance your motor will instantly die and come alive again, etc etc jerking motion; check your kill switch wires. check all wires.

[Carbs were flooded]

The other problem could be your high speed jets are clogged, or the float is stuck closed or open, this will cause a loss of power, not complete shut down but a bogging, if this is the case, then rebuild your carbs. although, if the float is stuck open, then fuel will exit the carb. Check your choke.

 

[steveo32]

Re: Motor cut out at WOT

There was no jerking or anything, I can't explain it I could just feel that it was slightly loosing power so I let off the throttle a little, throttle is not as responsive as a car so it didn't really do anything. And then it just died, while it started to die I moved the throttle to neutral but it had already died before I got it to neutral.

Also I think the fuel had sat over the winter and may have seperated. I didn't own the boat until March, But it ran fine on the muffs. I know I should of used fresh gas, but do you think that would cause the motor to cut out at wot.

Also thanks for the link the starter doe turn over and it acts normal except it just won't start. I took the spark plugs out and will let it sit overnight. Also it will act like it is about to start but then it goes back to just cranking over again.

 

[steveo32]

Re: Motor cut out at WOT

Can someone give me a link to a tutorial or step by step directions for taking the carbs off. And what do I need to look for? Pictures would be great.

Thanks

 

[HighTrim]

Re: Motor cut out at WOT

Start by checking spark and compression and go from there.

The spark should jump the gap on an inline tester a good 7/16 of an inch with a bright blue ZAP!! Compression should be around 100 psi but more importantly EVEN on all cylinders (within 10 percent).

 

[HighTrim]

Re: Motor cut out at WOT

Can someone give me a link to a tutorial or step by step directions for taking the carbs off. And what do I need to look for? Pictures would be great.

Thanks

What you should really look into getting is a factory OEM manual. Check www.ebay.com or www.outboardbooks.com for a factory reprint. It will be your best friend and pay for itself a million times over. This video may help if you decide to clean the carbs.

http://www.meegsonline.com/tmd/TMDsVideoChronicle2.wmv

 

[steveo32]

Re: Motor cut out at WOT

Also I checked the spark plugs again and they are coated with oil, so I think the oil gas mixture may have seperated and I think that could stop at motor at wot. I am pretty sure it is a fuel/oil issue but was unsure if that would make a motor run fine for 5 min at wot and then just die like that??

 

[steveo32]

Re: Motor cut out at WOT

Do I need a Owner's Manual or a Service manual?? I would assume a Service manual bu twant to make sure.

 

[steveo32]

Re: Motor cut out at WOT

Well cleaned the spark plugs off with wire brush, connected line to new gas and it started right up. Run it on the muffs for about 20 minutes or so. I think I will clean the carbs, because I am assuming that there was gas in the carbs when it was winterized so it probably has alot of varnish in there and that is probably why it flooded. What is the best way to de flood the carbs on the lake, if this happens again? Or is just waiting the only thing I can do? Next time I take it out I will go with a buddy so he can at least tow me back if it happens again.

Thanks

 

[tashasdaddy]

Re: Motor cut out at WOT

i have found if flooded, disconnect fuel line and tilt motor full up, allow carbs to drain then lower. then turn over a couple of times. to pump out what is left.

 

[darrklim2]

Re: Motor cut out at WOT

Well cleaned the spark plugs off with wire brush, connected line to new gas and it started right up. Run it on the muffs for about 20 minutes or so. I think I will clean the carbs, because I am assuming that there was gas in the carbs when it was winterized so it probably has alot of varnish in there and that is probably why it flooded. What is the best way to de flood the carbs on the lake, if this happens again? Or is just waiting the only thing I can do? Next time I take it out I will go with a buddy so he can at least tow me back if it happens again.

Thanks

I think it was more that the dirty fuel fouled the plugs causing them not to spark any more. I would guess with new fuel and cleaning the carbs you won't have this problem again. IMO

 

[Theoutdoorsman]

Re: Motor cut out at WOT

Too, you may have had bad plugs to begin with. I'd recommend you take along a brand new spare set of plugs with you next trip out. The problem may be solved??? If not, then I'd definitely take the advice given earlier in the thread, and check the spark and compression prior to jerking the carbs off the powerhead. You'll likely need the service manual before re-installing them. Turn the wrong screw's and you'll begin a search for another powerhead!! Purchase a service manual, even if you don't need it right away. If you plan to keep the outboard, you eventually will. Regards.......... ALAN

 

[steveo32]

Re: Motor cut out at WOT

The spark plugs were brand new.

Also today I was looking over the motor and making sure everything was nice and tight and discovered that only 2 screws were holding the cover in front of the carbs on and I could move the rubber gasket with my finger it was so loose. So I found some screws that fit in there and tighten them up and started it up again and it runs much smoother at idle than before. Now that a bunch of air isn't coming in. May have to adjust the mixture a little but will deal with that when I get out on the lake. For right now it seems to run much better and the plugs aren't fouling so I think all is well.

 

[steveo32]

Re: Motor cut out at WOT

This is a picture of the cover I am talking about, not my motor though.

 

[steveo32]

Re: Motor cut out at WOT

Well, just wanted everyone to know that I took the boat out to the lake and it ran great once it warmed up. It did stall on me when I left the boat launch, but it started right backup and i left the warm up lever up for a minute or so and then lowered the lever and put it into gear and it ran great.