PLEASE HELP ....1999 Johnson 90HP

[OneLuv1979]

OK i have a 1999 Key Largo Boat with a 90HP johnson ...

I was out today and was able to cruise for about 10minutes and then all of a sudden it lost power and went to just a crawl ... And the engine seemed like it was bucking & shaking just not running well ....

I let it sit for about 4 hours and after a minute of running it did the same thing .....

I am not a mechanic by any stretch but i surely do try ......

Anyone possible have a clue where to start or what it could possibly be ?

 

[crb478]

Re: PLEASE HELP ....1999 Johnson 90HP

What model Johnson? assuming it is a 99. It could be anything from your SLOW system kicking in to dirty carbs,air leak in the fuel lines to ignition trouble. I would start by doing a compression test and then verifying a spark on all four that will jump a 7/16 inch gap. Report those findings and then we can start to focus in on what it might be.

 

[jonesg]

Re: PLEASE HELP ....1999 Johnson 90HP

No alarms?

 

[OneLuv1979]

Re: PLEASE HELP ....1999 Johnson 90HP

Its a 1999 J90PLEEB

I removed the oil injection because i got a no oil light ....
The boat went out saturday with no issues , so i doubt the compression is bad ....It also ran great for about 10min today untill i was in a no wake zone and just cruise'n when it lost power and started running like crap and the motor started running funky ...

Tomorrow i will check the plugs and do a compression check ...
I will comment with my findings ...

 

[OneLuv1979]

Re: PLEASE HELP ....1999 Johnson 90HP

OK i pulled the plugs and they seemed flooded with fuel / oil ..
At least there not white , so im running a bit rich ....
Looking at the plugs they did not look properly gapped ...
So tomorrow i will replace the plugs and make sure they are properly gapped ...

Compression check showed 125-130 in all 4 cyclinders .... Really good news ...

My issue is after running for 10 minutes at idle it just idles way down and engine bucks .... Is it possible the engine powers down to protect it from something ??

Sorry i am clueless , but i know my fathers Yamaha will ...at least that is what he said it says in his manual ...


Anyone have any suggestions on what i might want to check ?

 

[jonesg]

Re: PLEASE HELP ....1999 Johnson 90HP

possible overheat putting it into SLOW mode.
test the temp sensor in the head, ground it to the block, ignition on.
it should beep the warning buzzer.

is it running hot?
hows the pee stream, ?
when was water pump last done?

 

[OneLuv1979]

Re: PLEASE HELP ....1999 Johnson 90HP

I had the water pump installed Friday , the issue happend Monday ....

I have only had the boat 3 weeks , so i decided to replace the thermostats and water pump and had a reputable shop do the work....

Once it started i cruised slow with the motor running like crap to the sand bar we hang out at , and let the motor sit for 4-5 hours , 2 minutes after it was started it ran like crap again ....
So im not sure about the overheating part , BUT where would the temp sensor be located ? I might as well check it ....
How do i ground it ?

any other suggestions ?

 

[HybridMX6]

Re: PLEASE HELP ....1999 Johnson 90HP

Wait until it's warmed up and starts giving you a problem again, then do a spark check. It sounds like you're dropping spark when it gets warmed up, causing a rough idle.
Could still be overheating also, so don't rule that out until you verify it's okay, but slow mode is just backing the motor down to under 1500rpm's or so, it shouldn't cause a bucking unless it's seriously hot.

 

[OneLuv1979]

Re: PLEASE HELP ....1999 Johnson 90HP

Bump

 

[HybridMX6]

Re: PLEASE HELP ....1999 Johnson 90HP

To do a spark check just go to a local auto parts store. You can get one for under $10. It will have instructions on the back of it. I just unplugged the spark plugs, then 1 at a time hooked the spark tester up to them and turned the key. My motor is not on a boat right now, so it's easy. Since yours is, have someone turning the key for you while you watch the spark. General consensus on spark gap to tst seems to be 7/16" or so. Mine was jumping a solid 1/2" gap. The tester is adjustable. It will be tricky on the water, but if you can get it to do it, just pull over and beach it for a minute and hop and and do it.
The bucking description sounds like it's dropping a cylinder or two, not safe mode. Not good to run it like that either, it will off balance the motor. if you have to to get back, then it leaves you no choice.
If it proves to be one side isn't firing, try switching the coils or whatever on either side and see if the problem follows it. If it does, then the part is bad. If the problem persists on the same side, it's somewhere up the ignition line. ONly do this stuff though if it's losing spark. If all cylinders retain spark when it's doing this, then your problem is elsewhere.
Give it a try and post back, we can go from there with what you find out.

 

[OneLuv1979]

Re: PLEASE HELP ....1999 Johnson 90HP

Thanks i will have to check that out ......anyone have any other suggestions ?
I was planning on putting new spark plugs in , with the correct gap and see if the problem continues ...

Wierd thing is when i got it back home on the trailer and hooked it uo to water , it ran crappy .... Then for 3 seconds it would run smooth then crappy for 15 sec ,off and on ...very odd ..




1 Quick question , i have a 99 J90PLEEB would this be the proper manual ?

http://cgi.ebay.com/ebaymotors/ws/e...name=STRK:MEWAX:IT&viewitem=&salenotsupported

 

[jtcarter]

Re: PLEASE HELP ....1999 Johnson 90HP

Sucking air or dirty carbs. Thats what i would assume since you didn't get any alarms. If it was going into slow, you'd get a alarm.

 

[OneLuv1979]

Re: PLEASE HELP ....1999 Johnson 90HP

I get a alarm beep when i first crank the ingnition ,but its just 1 quick beep and that is all i get ....

 

[HybridMX6]

Re: PLEASE HELP ....1999 Johnson 90HP

That's the "self test" I believe, just so you know it is functioning.
If all plugs were very wet with fuel, clogged carbs is an unlikely cause. Wouldn't hurt to have them gone through and rebuilt though, it's easy and you can do it yourself if you have the manual.
I don't know if that's the right one or not, I'll let someone else with more knowledge on that ring in.
I have two I've got from ebay, but they only covered my motor, exact year and hp, or exact year and 2 hp ranges, 60 and 70.

 

[jtcarter]

Re: PLEASE HELP ....1999 Johnson 90HP

I get a alarm beep when i first crank the ingnition ,but its just 1 quick beep and that is all i get ....

Thats just letting you know the alarm system is working.

 

[crb478]

Re: PLEASE HELP ....1999 Johnson 90HP

do you have a water separating filter. Are you sure your fuel is good. Get/borrow a small portable tank with fresh gas and see if that eleminates the problem.

 

[OneLuv1979]

Re: PLEASE HELP ....1999 Johnson 90HP

I do not know of a water seperator ...where would it be located ?
I looked for some type of filter but couldnt find anything ...

The gas is all new , when i switched it over to MIX rather then oil injection i drained the tank and added all new gas ... I poured the gas that was in the boat in my Jeep and the Jeep is running great used all the gas allready to so im sure its not the gas ......

Plus the fact that it did this once before i switched over to Mix and had the water pump done ....

 

[OneLuv1979]

Re: PLEASE HELP ....1999 Johnson 90HP

ok i didnt get a chance to check spark ....

But i did replace the spark plugs , gapped at .30 and i didnt get 20 feet and it started again ....
I pushed in the choke , nothing , i pumped the gas ball and sure anough it cleared up and ran great ....

At 3500-5000 RPM it runs fine no hickups , at no wake slow it starts back up , a pump of the ball and its running fine again ...

I have looked for a water seperator and i do not have one ....


I will look for a leak on the hoses , it was raining here so i gave it a pretty good look but will look better tomorrow ...

Maybe fuel pump ? I looked all over for a fuel filter , there has to be one somewhere but couldnt find one ...

Any other ideas on what i can do ??
Im despirate ...to get this thing fixed...and really learning as i proceed ...

 

[OneLuv1979]

Re: PLEASE HELP ....1999 Johnson 90HP

ok i didnt get a chance to check spark ....

But i did replace the spark plugs , gapped at .30 and i didnt get 20 feet and it started again ....
I pushed in the choke , nothing , i pumped the gas ball and sure anough it cleared up and ran great ....

At 3500-5000 RPM it runs fine no hickups , at no wake slow it starts back up , a pump of the ball and its running fine again ...

I have looked for a water seperator and i do not have one ....


I will look for a leak on the hoses , it was raining here so i gave it a pretty good look but will look better tomorrow ...

Maybe fuel pump ? I looked all over for a fuel filter , there has to be one somewhere but couldnt find one ...

Any other ideas on what i can do ??
Im despirate ...to get this thing fixed...and really learning as i proceed ...

bump

 

[HybridMX6]

Re: PLEASE HELP ....1999 Johnson 90HP

If using the choke/primer doesn't do anything, but pumping the bulb on the hose does, either the bulb is going bad, the tank vent is not open (not likely b/c that would suck the bulb and make it collapse), or the fuel pump is going bad. Personally, I'd go grab a small portable tank and a new hose/bulb assembly. Put a few gallons in it, hook it up, and run the boat, see what happens. I twon't hurt to have a spare around anyways, even if it's not the problem. I have 2 spares myself. If that fixes it then something is wrong with the bulb or the fuel pickup in your gas tank. If not, I'd suspect the fuel pump is going bad. You should be able to pick up a new small portable tank with hose assembly for $40 or so.