My 50 hp 1989 won't rev

[tiller7104]

I was out on the river today and initially my engine ran great... I ran about 2 miles up river and I started looseing power a little at a time until it ran about 200 above idle at full throttle. It idles fine and shifts fine and when in gear it sounds fine I just have no or limited power...I get a little more than idle enough to limp me back to the ramp. Yhe funny thing is the engine sounds fine, at WOT I get little better than Idle and again this got progressivly worse as I ran up river? Please help I am at a loss! Thanks in advance, Stuart

 

[roscoe]

Re: My 50 hp 1989 won't rev

Did the gas line bulb go soft/flat?<br />Do you have the vent on the gas tank open?

 

[tiller7104]

Re: My 50 hp 1989 won't rev

Roscoe, thanks for the reply. I do notice that the inline fuel filter does not stay full? But I have never had to pump it to restart the engine, and I have never seen it flat? It is a permanently mounted tank, and it vents to the transom (it is not a manual on/off vent) I guess I should check to see if it is funtioning properly. If this was the issue wouldn't the moter run crappy? It runs fine but I just get no power, and the rpms will not rise? I am going to try your suggestion today, just trying to think ahead if this is not it. As always your expert help and advice is greatly appriciated. Thanks Stuart

 

[tiller7104]

Re: My 50 hp 1989 won't rev

Just a thought the gas cap is almost impossible to get off if the engine has been running, which goes exactly with what you are saying! I guess it is creating a vacume in the tank....now you have me thinking LOL

 

[tiller7104]

Re: My 50 hp 1989 won't rev

Well I checked the fuel tank vent and it is clear. I blew through both ends and it is very clear.I checked the pick up tube and the screen on the bottom is fine. I blew into the fuel fill and air freely flowed out of the vent. I took the sender out and visualized the inside of the tank and no leaves etc. Now I am at a loss, is it electrical...Fuel...Do I have an exhaust leak in the engine case that may me chokeing out the engine. I know that I should test this boat with the engine cowl off and the fuel cap off but the only body of water near me is a river, and break downs are not an option LOL. Any more help would be great!! Where is Roscoe when you need him. Thanks again in advance, Stuart

 

[roscoe]

Re: My 50 hp 1989 won't rev

I guess there is only one thing I can suggest, then it is back to square one diagnosis.<br /><br />Head out to the river, take a friend in another boat, or a small kicker motor, so you don't get into trouble. Or maybe tie the boat to the dock with a couple of good strong lines.<br /><br />Run it.<br />If it starts to die out on you, squeeze e fuel bulb.<br />See if the motor picks up. <br /><br />If not, pull off the cover and see if more fresh air to the intake will help. If it does, great, couple gaskets to repace on the exhaust side.<br /><br />You could also take a small squirt bottle with premixed fuel in it, and squirt it directly into the carb to see if it helps.<br /><br />What makes an engine run? spark-fuel-compression.<br /><br />You may be loosing spark after the coils heat up. If you have troubles again, check for spark on both plugs right away.<br /><br />If it picks up when you squeeze the bulb, we know it is fuel related. Could be a leak the fuel line, allowing it to suck in air. Any of the fittings along the length of the line could be suspect. Could be a stuck float or valve in the carb not allowing the bowl to fill. Could be debris in the carb bowl. Could be an air leak around the fuel pump/damaged gasket/loose pump, etc.<br /><br />I know, a pain in the butt.<br />But we have to figure out if it is spark, fuel, or compression problem.

 

[tiller7104]

Re: My 50 hp 1989 won't rev

Well an update for today, thanks for the impute and it was back to square one!<br />Today:<br />1. Replaced Head Gasket (Had a small spot on the lower cylinder metal ring, white like maybe there may have been a bit of water on plug?)<br />Both cylinders compression checked at 125 pounds<br />2. Replaced all fuel lines and clamps and fuel bulb (hand pump).<br />3.Did a power test, with engine running in a barrel of water removed a spark plug wire one at a time, both cylinders are firing.<br /> <br />4. Started and ran engine in barrel after all repairs were done, seems to run smoother?<br /><br />I think that some of the fuel line, and connections looked suspect. I also found that the fuel filter had 1/4" inlet and outlet. I made sure that everything from the fuel tank to the fuel pump was 5/16" with no restrictions.<br />I am going to out it in the river tomorrow and see if this did anything? I am going to try the whole running it with out the cover off thing also. Is there anything that I am missing? Do you think that I should do anything else before I put it in the river tomorrow? Any suggestions for while I am out there? Keep your fingers crossed! Stuart

 

[roscoe]

Re: My 50 hp 1989 won't rev

Lets hope the fuel line took care of it.

 

[tiller7104]

Re: My 50 hp 1989 won't rev

Weather to poor to get it wet, hopefully over the weekend!

 

[Docdoc]

Re: My 50 hp 1989 won't rev

Just one other thing and it is simple enough to do. You might check the fuel pump diaphragm and see if it is nice and soft or if it is hard (maybe even has a tear in it). If there is any doubt, replace it. It only costs ten to fifteen bucks.

 

[tiller7104]

Re: My 50 hp 1989 won't rev

Thanks Doc, I just went thru a rather extensive go over on the outboard.....see list<br /><br />1. Replaced Head Gasket (Had a small spot on the lower cylinder metal ring, white like maybe there may have been a bit of water on plug?)<br />Both cylinders compression checked at 125 pounds<br />2. Replaced all fuel lines and clamps and fuel bulb (hand pump).<br />3.Did a power test, with engine running in a barrel of water removed a spark plug wire one at a time, both cylinders are firing.<br />4. Replaced fuel pump diaphram and applicable gaskets.<br />5. New plugs<br /><br />Have any of you ever heard of an electrical issue causeing my decreae in rpm's?<br /><br />One other thing, I sat on the river for about 3 hours fishing without the outboard running (should have been enough time for a good cool down it was 50 degrees out) When I restarted it the problem did not improve, I would have expected it to if it were a heated coil etc? Right? I know my way around the wrenchs but this one has me stumped! ANY SUGESSTIONS WELCOME Thanks in advance, Stuart

 

[roscoe]

Re: My 50 hp 1989 won't rev

So I'm guessing you took it out over the weekend and had the same results, started out fine then slowly lost rpm?<br /><br />Or did it run slow right from the start?<br /><br />Did you try spraying some premixed fuel directly into the carb to see if it will pick up?<br /><br />Gonna stay with the fuel problem idea and suggest you rebuild the carb. Could be a sticking float or valve restricting fuel to the carb.

 

[tiller7104]

Re: My 50 hp 1989 won't rev

Started out better than I ended last time but still started out with less than half the r's I should have then progressively got worse. I limped back to the ramp just barely above idle. I did not try the mix in a squirt bottle, I forgot....if this works what does that mean? Rebuild the carb? Thanks for the reply I am going to try this tomorrow night. As always thanks in advance!

 

[roscoe]

Re: My 50 hp 1989 won't rev

Carb rebuild would be on the adjenda if a squirt of gas helps.

 

[tiller7104]

Re: My 50 hp 1989 won't rev

UPDATE.........<br />Test ran today, -ran with cowl off.<br /> -Tryed spraying gas into the <br /> Carb while running<br /> -tried pumping fuel primer ball<br />Still is doing the same thing, the only difference being is that it ran like crap right from the get go. I am going to rebuild the carb anyway. Who knows maybe that will help? Any suggestions?

 

[raveng60]

Re: My 50 hp 1989 won't rev

i would check the linkage to see if the carb is in fact opening all the way when you have full trotle!!! let us know.

 

[tiller7104]

Re: My 50 hp 1989 won't rev

I left that out...it is good thought! It is...When I ran it today I looked at the throttle linkage and it is at WOT on the Carb!

 

[tiller7104]

Re: My 50 hp 1989 won't rev

I think I found something... If you look under the flywheel, it is filthy, and there is an ton of red/brown gummy debris that is new on the block right under it. I know for a fact that this was not this dirty 3 weeks ago. It looks recent almost like something is hung up. I notice that there is linkage going to it that also connects to the carb linkage. Is this the culprit?

 

[roscoe]

Re: My 50 hp 1989 won't rev

Was afraid we would end up there.<br />Sounds like the stator is disintegrating/melting down.<br />You can check the stator with a multimeter, check for continuity and resistance on the two yellow wires.<br />You can also check the output of the stator if you have a manual and a decent meter.

 

[tiller7104]

Re: My 50 hp 1989 won't rev

Well maybe at least we are narrowing it down. I tried removing the flywheel today. I used a snap on 5/16th sheel puller, this just pulled the threads out of the puller holes. I tried a 3 jaw puller that just started flexing the flywheel. Am I missing something? I heated it and soaked it with wd40 but as of yet no luck removing it. Is there a majic bolt that I am missing LOL Any suggestions Thanks