Johnson 35hp Running Problems

[beermunk]

First, i'd like to say hello to everyone and let ya'll know that i searched for this problem before i'm posting it here.<br /><br />okay, the last few times i've taken my boat out, it's run fine for an hour or maybe more... and then suddenly it'll sound like the rpm's just jumped up, and it'll slow down and then sputter out. <br /><br />then, i'll spend the rest of the time cranking the electric start, where it will eventually get going again, but i'll only be able to give it a little throttle in forward gear or it'll sputter out again. this will happen the rest of the way back to the dock. i'm not that mechanically inclined, but i can fix stuff if i need to. any suggestions on what to start looking for?<br /><br />the other thing is, that i bought some gas the last time out from a place right off the river, i'm not sure how much there gas get's used, but i'm going to get rid of it and use some new stuff from a gas station. so what's the best way to dispose of gas? i'm too green to just throw it into the woods.. but what else is there?

 

[E120B]

Re: Johnson 35hp Running Problems

Kinda Sounds to me like your water pump is on it's way out.. If you don't already have one get a manual for the motor they are aviable here on iboats for under 50 bucks that will have detailed instructions on how to change the impeller.

 

[beermunk]

Re: Johnson 35hp Running Problems

the manual's are under $50 or the water pumps are?<br /><br />so the water pump is not cooling the engine and then it's dying or the engine is not letting itself run without a fully functional pump?

 

[rwise]

Re: Johnson 35hp Running Problems

the impeller for the pump is $20 - $30 for most. <br />overheating could be the problem.

 

[beermunk]

Re: Johnson 35hp Running Problems

so what happens when the motor overheats? this is an early 80's motor, so i can't imagine that it has some sort of reset switch to it...

 

[phatmanmike]

Re: Johnson 35hp Running Problems

when it over heats, you buy a new motor or get that one rebuilt. yes its that serious. your outboard is a 2 cycle and it works really hot. it has twice the number of explosions as your cars, not to mention it spins 5k all day. in less than one minute without water, your motor is junk. i know this from experience

 

[beermunk]

Re: Johnson 35hp Running Problems

that sounds frick'n frightening....

 

[rickdb1boat]

Re: Johnson 35hp Running Problems

The only problem I have with the waterpump theory, is that he ran it an hour before the problems occured. It would have blown by then if it was the pump. The RPM's jumping up indicates a lean condition right before it died. I would check the simple things first like the fuel tank vent to be sure it's clear. Give the choke a shot or 2 when it starts to die and see if that helps. Could be the primer bulb gone bad. Fuel pump going south. Just some thoughts. Next time you take her out and it starts this, pull the cowl and feel the engine block above the spark plugs. If you can hold your fingers their for a few seconds, it's probably OK. If you get burned right away, it's hot and overheating. If you could do this on muffs in the driveway, it would be better. Then you could shut it down right away to avoid damage and all it takes is letting it idle for a while...

 

[beermunk]

Re: Johnson 35hp Running Problems

yes, i failed to mention that when i filled up i closed the vent nut thing on the fuel cap, then when hit the high rpm's i looked back and the tank was compressed from not having the valve open. then i opened it back up, but it didn't ever run correctly all the way back home... just did the start/putt putt/die if given to much gas game.<br /><br />this went on for the next half an hour, until i got to the dock. i figured if it had just killed because of gas, it would've worked that out by the time we got back.

 

[rickdb1boat]

Re: Johnson 35hp Running Problems

But, it did run good before you noticed the fuel tank vent was closed??

 

[beermunk]

Re: Johnson 35hp Running Problems

yep, like a champ... for exented periods up the river, and then shut it down, and then more up river driving...<br /><br />christ, it made it 3/4 of way back from the furthest point up back to the dock and about a mile out or so the motor sound went up an octave or two, i thought i hit something and it jumped out of the water, but i felt or heard nothing... then it slowed down and killed. the rest of the trip was me starting it, running it for about three minutes, and then watching it die.<br /><br />also, to get it restarted, i had to wait a few minutes in between, because it would just sit and crank, almost catch and start, and then put out.<br /><br />i checked the bulb a few times and it was firm... so i'm pretty sure gas was in it.

 

[rickdb1boat]

Re: Johnson 35hp Running Problems

Check the fuel pump diaphram. Could be it collasped or distorted because of the restriction. I would replace the bulb also, as it could now be the problem, even though it pumps up solid. It has a check valve in it that may be screwed up at this point. Cheap stuff first!! It ran good until then, so it has to be related...

 

[beermunk]

Re: Johnson 35hp Running Problems

thanks for the advice! how do i go about checking to see if the bulb is FUBAR?

 

[rickdb1boat]

Re: Johnson 35hp Running Problems

Remove it and shake it. If it rattles, it's no good. But for the price of one, I'd opt for a new OMC one, not generic..

 

[beermunk]

Re: Johnson 35hp Running Problems

thanks, i'll check that out when i get home tonight... it would be great if it was something small and stupid like that!

 

[Brew2]

Re: Johnson 35hp Running Problems

Re getting rid of your questionable gas....try your local dump/landfill. In my neck of the woods they have a special station for getting rid of oil, gas, paint, batteries, etc. I believe most of this stuff is recycled.<br /><br />Cheers.

 

[beermunk]

Re: Johnson 35hp Running Problems

sounds good. the more i think about the bulb being the problem, the more i think it sounds exactly like what was happening. God i hope that's it.

 

[beermunk]

Re: Johnson 35hp Running Problems

okay, went home real quick and took the hose off and shook it... definate rattle in the bulb. is this the problem?

 

[beermunk]

Re: Johnson 35hp Running Problems

so is that the problem then? i hear a rattle in the primer bulb and that means it has gone bad?

 

[rwise]

Re: Johnson 35hp Running Problems

They are not costly, and if it's not then you have a spare. (throw it away and replace it) I have to agree that it sounds like a fuel delivery problem. Can you keep it running by pumping the bulb? I had something similar hapen with my 35, random times it would act up. found a single flack in the bowl of the carb, removed it ran great for a while then started again. opened carb and thers another flack, rebiult the carb no more problem. and it acted verry much like you discribe, but I could choke it and keep it running. do look into the fuel pump also.