bogs when trying to throttle up

[guywithboat]

Hi All,

I have a 72 Evinrude 50hp, 50272C. Starts great and runs good upto about a 1/4 throttle. If I give it more it bogs. Interstingly if I hit the electric choke and then release it, the rpms increase and I can throttle up a little for a few seconds. Any ideas?

Compression is great. Is there a high speed adjustment? I am unable to find it right now.

 

[guywithboat]

Re: bogs when trying to throttle up

BTW in neutral it screams, I am referring to when it is in gear. (Forward)

 

[MELSNER]

Re: bogs when trying to throttle up

I had a similar problem last year, it was a hairline crack in the inline fuel filter of my 86 70hp. The crack only only opened when you throttled up, then it sucked air.

 

[guywithboat]

Re: bogs when trying to throttle up

I have a brand new inline filter on mine. I used it on my other engine and didn't have that issue. I am replacing all the old fuel lines here in a minute, they are leaking a bit. Thanks.

 

[Evinrude Boater]

Re: bogs when trying to throttle up

Can you feather the throttle and eventually get it to WOT?

 

[guywithboat]

Re: bogs when trying to throttle up

No. I have replaced all the lines. I have been unable to take it back out yet. Plan to rebuild carbs Monday and take it back out.

Till then, ideas are welcome.

 

[Texasmark]

Re: bogs when trying to throttle up

Fuel starvation. Check search for it.

Mark

 

[robtown]

Re: bogs when trying to throttle up

I have the EXACT same issue on my 72 50 hp Johnson. You describe the my issue to a tee...

let me know what you find out and I'll do likewise...

R

 

[jtexas]

Re: bogs when trying to throttle up

Classic symptom of fouled carb(s). Remove, disassemble, soak in carb cleaner, blow out passages with compressed air, reinstall with new carb kits.

 

[robtown]

Re: bogs when trying to throttle up

Pulled my carbs, cleaned them up. Found some serious blockages in the float bowls, boulders and gunk..., I doubt the top carb was even contributing. I don't have ready access to carb kits so I'm reinstalling as is for another test run...
Feel pretty good about it. Can't be any worse than it was.

Thanks,

R

 

[rickd20006]

Re: bogs when trying to throttle up

I have the exact same problem.
Did you figure it out yet.
This is driving me crazy.
I just can't figure it out. Did my carb kits. Floats level when inverted. Needles and seats. Carbs looked brand new inside. Don't think I have blockage. Didn't do welch plugs. Compression good. I have to jam the throttle down fast to get going but I can't throttle up slowly.
Has anyone had this problem and been able to correct it.
I haven't heard of anyone being successful as of yet.

Thanks

 

[jtexas]

Re: bogs when trying to throttle up

rickd, carb kits solved that problem when I had it 3 years ago. I hope they solve the problem I'm having now which is dropping a cylinder but only at idle and only in the water (idles great on the muffs). Be a week before I can finish up & test it.

It looks clean as a whistle, but...you can't see inside the passages...did you soak 'em good in something like B-12? flush 'em with carb cleaner in a spray can?

which motor you working on? have a manual?

One nuther thing to look at...the timer base, under the flywheel, linked to the throttle, gets pushed forward to advance the spark when you throttle up, ...should move forward smoothly, if it sticks, could give you that kind of symptom. Or if it doesn't start moving at the right time, check "link & sync" in your manual, usually should start moving just before the throttle plates. Not sure whether this adjustment can be made on pre-CD ignitions.

Also maybe doublecheck your idle speed is good.

 

[Jzx2sr]

Re: bogs when trying to throttle up

I have a similar problem, however I smell unburnt fuel. Same problem ?

 

[Craig W]

Re: bogs when trying to throttle up

I might be off in left field here - but could there be water contamination in your fuel??

I've run into a very similar problem with my Yammy 115 this season (never had it before)..I've been knocking myself out researching the "bogging when trying to run at throttle under load" and things started directing me toward water in the fuel. I pulled my fuel filter and drained the contents of the bowl into a clear pill bottle for further investigation . After it sat for a couple minutes a layer of water showed up! I know it's being discussed everywhere right now, but the ethanol in our gas (increasing?) could be starting a whole new set of headaches for us...?

 

[rickd20006]

Re: bogs when trying to throttle up

Hey thanks all for your input
Jtexas what you said about the timer base could explain why I can throttle up only if I jam it down quickly and not slowly. Could be sticking I never soaked the carbs at all.
What I am noticing at idle is gas accumulating inside the throttle chamber. Kinda spitting. Should I see gas at the bottom of the shaft within the throttle chamber. Right behind the butterfly. Sorry don't know the terminology
I have a manual. 1983 70hp Johnson
Thanks

 

[VADER8674]

Re: bogs when trying to throttle up

hey guy have you got your power pack in yet did it fix
it let me know something

 

[VADER8674]

Re: bogs when trying to throttle up

it looks like you are trying to become a superior officer with all your post tonight you past me but with money to spare next payday puts me hopefully back in the water and any boat of mine in the water means all my spare money is going there too lol ...

 

[guywithboat]

Re: bogs when trying to throttle up

The carbs are fine. I tested the rectifier as well. I just installed the power pack. I hope to take it out tomorrow.

In my case it is electrical. My plugs, wires and coils are all good. Wish me luck.

 

[jtexas]

Re: bogs when trying to throttle up

rickd,
Carb spitting gas is symptomatic of reed valves - not sure what else - probably be a good idea to start your own thread - ask about reeds in particular - get somebody more knowlegeable about that involved - wouldn't want to get guy's thread all cluttered up here.

 

[VADER8674]

Re: bogs when trying to throttle up

GUY DID YOU GET HER OUT IM GOING OUT TOMMORROW IN EITHER MINE OR GARY,S CALL ME IF YOU ARE OFF WELL HOOK UP AND SEEEE IF WE CAN GET HER GOING