Johnson 10R76H Fuel line to tank

[Ozark littlefish]

Sir, I just bought an old Johnson 9.9hp for my 12' V-hull. After reading everything here about it I was able to get it running very well, maybe to well. It wants to stand the boat on it's tale. I must admit, it's a very small boat, it is however, rated for 10hp, and I am a very large boy, 260lb, rated at 210lb. In an effort to move weight forward I have relocated the Fuel Tank to near the bow by ading 8' of fuel line to the tank. My question, Gentelmen, am I going to starve the engine of gas, or more importantly oil ? It dos seem to loose RPMs after a short time at WOT. Would a New fule pump help, maybe off a larger motor ?<br /><br />Thank You All, for the info you have provided allready.

 

[wilde1j]

Re: Johnson 10R76H Fuel line to tank

It's fine with the long fuel line. Did it lose any RPM's with the std short line?

 

[Paul Moir]

Re: Johnson 10R76H Fuel line to tank

Welcome to Iboats!<br /><br />First, you can prove you've got a fuel deliver issue by pumping the primer bulb when it bogs and seeing if it picks up. I think you are but we might as well be certain.<br />Likely you're drawing air into the line somewhere along the way, and I'd try to rule that out first if I were you. Sometimes it's pretty obvious because a little fuel will be leaking out around which ever fitting is leaking. The most common culprit is the quick connect on the outboard, because the o-ring in it wears out pretty rapidly. You can usually just replace the o-ring.<br />I doubt the extra 8' of line is too much for the pump, unless you went with something a lot smaller than 5/16" ID. The 9.9 just doesn't draw that much even at full throttle. But it's possible that it's turned up some other problem like a weak fuel pump, restricted primer bulb, clogged filter, etc.<br />I hope that helps!

 

[Ozark littlefish]

Re: Johnson 10R76H Fuel line to tank

Not that I could tell but I was not able to run WOT with the boat pointing up. Could Carburator float cause this problem ?

 

[Ozark littlefish]

Re: Johnson 10R76H Fuel line to tank

No fuel leeks, all fitings and hoses new. The bulb stays firm.

 

[Xcusme]

Re: Johnson 10R76H Fuel line to tank

Since you will be mixing your fuel with oil (50:1), you won't be starving the motor for oil. As for loosing RPM's after a bit at WOT, are you sure the motor is not overheating? Does manually squeezing the primer bulb make any difference in the RPM's? What have you already done to " get it running very well, maybe to well"?<br />Trying to retrofit another fuel pump off of a larger motor is not the answer. Getting what you have now (factory designed parts) is.

 

[Ozark littlefish]

Re: Johnson 10R76H Fuel line to tank

the motor was 124F at the hotest spot with my IR thermometr. Squesing the primer bulb dos not make any diference. As to what I have done already, I took everything off but the head and replaced, the lower unit seals, the water pump assy. the recoil spring and rope, the points, the curberator kit, but I could not finde a float, and all the fuel lines and fittings

 

[Paul Moir]

Re: Johnson 10R76H Fuel line to tank

If squeezing the primer does nothing to help it at full throttle, then you've ruled out the tank, hose, primer, fittings, fuel pump, filters (if present), and the carb's needle and seat. I'll leave this to the folks who know the 9.9 better.

 

[Ozark littlefish]

Re: Johnson 10R76H Fuel line to tank

As strange as it seems, I like it when things DONT work. My only real consern was damaging the motor by using a long fuel line. <br />I keep coming back to the carburator float, it floats in a container of gas but it looks like something Rover left in the front yard. As soon as I find one, I will replace it. Probably replace the fuel pump to. <br /><br />Do Ignition coils quit at full load and then start working again?

 

[Xcusme]

Re: Johnson 10R76H Fuel line to tank

If the float you have is cork,it's best to replace it with the newer plastic type. As for the fuel pump,I'd hold off for now. As was mentioned, manually working the primer bulb and seeing no change in motor performance, rules out the pump. If those are the original coils, yes, you could have a problem that will show up under the full load at WOT. Inspect the coils for any cracking and check to be sure they are properly mounted and indexed with their mounting bosses. BTW, you have done a sync and link, right??

 

[Ozark littlefish]

Re: Johnson 10R76H Fuel line to tank

Both coils have crackes in the plastic and I did not sync and link.

 

[Xcusme]

Re: Johnson 10R76H Fuel line to tank

Well, there you have it. Those coils won't get better over time, they should be replaced. The newer coils are better made, and are not that expensive. Replacing the coils is an easy operation. Be sure to install the coils one at a time so you can see how they are wired (3 connections, one to ground, the other to the points and spark plug wire). Be sure the coils are mounted properly. Surface A and surface B should be flush. This insures proper coil to flywheel clearance.<br /><br />

 

[Ozark littlefish]

Re: Johnson 10R76H Fuel line to tank

Gentelmen. I do thank you. There are not many places left where a beginer like me can go to ask stupid questions and have a reasonable expectation of tolerance and sound advise. <br /><br />Xcusme, where did you get a picture of my motor?<br /><br />Thanks Again

 

[Ozark littlefish]

Re: Johnson 10R76H Fuel line to tank

I just wanted to let everyone know how it turned out. $75.00 worth of coils and a carburator float, 2 mashed fingers, a link and sync fourteen cus words and a d-carb procedure....and I'l be a ............ it works! Idels smothe, runs strong, startes easey. It will go another 30 years.<br /> <br />During the sync and link I noticed the carburator dos not open up completly. The "buterfly" is aboyt 5 degres from paralell at WOT. Is this important ?<br /><br />THANKS