Hot, humid weather starting issues

[stratorod]

2004 Johnson V4 90. Good running motor. Well maintained. Motor starts and runs great. However, when fishing on a hot, humid day (mid 90s or higher), after working a spot over good (sitting for awhile without running), motor is sometimes finicky about starting. Friend has a V6 150 and has same problem. His was getting really bad until one day we replaced the fuel line bulb, fuel line to the tank, and installed a water filter/separator. Helped, but still has same problem once in awhile. This is just noticeable in hot humid weather. Anyone else have a similar problem? Any ideas? Not really an issue unless one would have to make a quick start to get out of the way suddenly. TIA.

[ChampioNman]

Got a model number? There are a couple styles of 90 HP Johnsons for that year.

[stratorod]

Hello! Yes mine is a 2004 J90GLSRM, and my friends is similar in design except it is a 150 and an 02 model J150PLSNF. We took my friends boat out fishing yesterday. His is acting up real bad again like last year. In fact, we had to cut the trip short. Here is what happened, and I am afraid mine is heading down the same road. Started out great. Ran great. Ran about two or three miles and fished for about 2 hours. Was very hot and humid on the lake. Got ready to move. Started engine. A little hard to start. Idled a little rough. Throttle down to take off. Dies immediately. Repeat 4 or 5 times then takes off and runs fine. Fished some more. Got ready to move again. Start engine. Idle rough. Dies. Repeat two or three times. Same result. Start engine and try to throttle quickly before dying--dies immediately. Repeat 2 or 3 times. Finally, engine takes off, except this time engine is trying to die as we are running. Loses power, picks back up, loses power, picks back up. It does this as we are trying to make it back to the ramp, which we finally do. Last year in July his did the exact same thing and here is what we did (hasn't had any problems since--until now):

Decarb engine with Seafoam Deep Creep
Cleaned fuel filter (wasn't bad) and replaced fuel filter gaskets
Replaced fuel lines and added fuel/water separator
Checked the throttle roller arm timing adjustment (ok)
Added Seafoam to fuel

Ran fine after that.

Carbs have never been removed for cleaning (his or mine)

Any info appreciated. Thanks!

Added: I forgot to mention that we replaced the fuel line primer bulb, but I don't think it was an OEM bulb. I just read one of the other posts and am wondering if this might be an issue? If the non-OEM fuel primer bulb lays at the back of the boat where the transom is, and constantly is exposed to water and wave action, maybe water is getting in somehow? Just reaching for straws here.
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Modified by stratorod at 10:51 AM 6/20/2010


Modified by stratorod at 10:54 AM 6/20/2010

[stratorod]

This past weekend we took my buddy's boat. The 150 was really acting up. We finally discovered that the engine was losing prime. After running then stopping to fish, the motor would start but would not idle, and would die when attempting to come out of the hole. I went to the back and primed the motor with the bulb and bingo! Starts, runs fine. That is until stopping again or trying to idle. Engine dies when idling. I am thinking a restriction between the bulb and tank, maybe in the pickup tube, or possibly a tank vent/gas cap? The fact that it dies when idling tells me that it is being starved for fuel at low RPM but pulls enough to run at WOT. This is a new OEM fuel primer bulb. I remember a time or two his original bulb collapsing a time or two. Whatever his problem is, I am sure mine is developing the same issue. Were getting closer. Just have to nail it down.

[ChampioNman]

If you do a search on vapor lock or engine dying 60* we have posted numerous remedies.

[stratorod]

I am also leaning toward the anti-siphon valve. Not quite sure how that thing comes out of the tank. I have posted threads on the Stratos board asking for help in this area. I have the 45 degree elbow type. Has a large nut at the base of the fitting next to tank. Looks almost as though it is threaded into the tank? Any info appreciated.


Modified by stratorod at 7:39 PM 7/19/2010

[ChampioNman]

The pickup tube is screwed in to the tank then the fuel fitting (anti siphon valve) is screwed in to it. Hold the pickup with a 3/4" wrench then unscrew the fuel barb and put it in a vice. Knock the ball and spring out.

[buster502]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by ChampioNman &raquo;</td></tr><tr><td class="quote">If you do a search on vapor lock or engine dying 60* we have posted numerous remedies. </td></tr></table>
go back and read this again

[stratorod]

Thanks very much Championman for taking the time to read my rambling and reply to it. This will be very helpful. I did try to find this info by searching first but no luck. May have overlooked. I also e-mailed INCA Company but no reply just yet. Very best regards, Rodney.

P.S. I'll post results when I have a chance to remove it and test.

[stratorod]

Took out the anti-siphon valve and tried it out this past weekend. There was a noticeable improvement but it did die on me once idling. She started back up and went on her way however and I never did have a problem coming out of the hole like I did before I took it out. Initial thoughts are that it was at least part of the problem. I am going to put in a new water pump kit real soon. May be reaching here, but since the engine seems to perform better in cooler weather perhaps the water pump (now on its 5th season) is not cooling the engine at idle and slow speeds sufficiently as it was before due to its age. Thoughts? TIA. Oh, and thanks to everyone for all the input.