1984 E185TLCRS Won't Rev Past 3000 rpms

Joined
Sep 15, 2020
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Like many I have a new to me boat that has put me through the ringer trying to get it running right and reliably.

My latest issue is last time out at WOT I couldn't get the boat to rev past 3000 rpms and was running around 18 - 20 mph. What has lead me to this point? Let me tell you the tale.

Motor is 1984 Evinrude V6 185HP E185TLCRS (VRO has been removed before I owned it).

Earlier this season I identified that the rectifier was on the outs (intermittent tach and multimeter showing no increase of voltage while running on the water at the battery). Tested the rectifier following some very helpful steps and replaced. Tach now is stable and showing good charge at the battery. In addition to that I had also read and heard that older Evinrude motors actually run better using Champion "J hook" spark plugs and not the NGK open gap spark plugs. So I swapped those out. When testing on the water I got an alarm beeping steady and so I of course idle back and shut it down. Let it sit for a bit and started it back up and alarm still was going off. Back home I limped, swapped out the "J hook" plugs with the open gaps and waited for my next test. Next time out same thing happened alarm went off. So back to shore and naturally I replaced the nearly brand new water pump (less than 10 hours on the replacement) and back out to try again and again alarm went off. This time I noticed that my fuel line was horribly pinched and began to hope that maybe that was the cause of the alarm. So added a nice fuel line hangar to ensure it can't get pinched anymore and this time out the alarm sounded a quick beep when first starting and never again. I had a laser gun to check the temp at the heads as well this time and both were right at 130 degrees F (after running at WOT) at idle. But I cannot get it to go past 3000 rpms now. I am wondering if there is some electrical fault that is causing the motor to stay in S.L.O.W mode because of the previous alarms thrown on previous days? What else can I look for?

Before the alarms and recent rectifier replacement (when I did get results on the Tach) at WOT I would be around 5500 rpms (give or take) and according to my GPS system that would be right around 35mph.

Overall work done since I have owned.
Replaced the port side head, gasket and water jacket cover (bad compression on one cylinder when I bought it).
New thermostats for both heads.
New water pump kit x 2
New power pack on the starboard side
New spark plugs x 2
New rectifier
Lots of other miscellaneous stuff (e.g. increasing the length of the fuel line from the tank to the motor and adding the hangar so it won't pinch).

I would really appreciate the help of the experts on where and what to look at next. Happy to answer any and questions to help narrow things down.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
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38,876
Facts------There is no S.L.O.W. mode on a 1984 model !----Post your compression numbers that you have today.----Then check for spark.-----It must jump a gap of 3/8" or more on each lead.-----Are the 6 high speed jets in the carburetor bowls confirmed to be clean, yes , no or no idea where they are ?----Flywheel key checked ?
 
Joined
Sep 15, 2020
Messages
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Hi racerone,

Thanks for taking the time to respond. That is very helpful to know that my model doesn't have the S.L.O.W mode. I will remove that from my various investigations going forward. I will check compression and post tonight. I have a previously checked for spark with a spark tester and all seemed good (that was after the power pack replacement on the starboard side about two months ago). I haven't checked the carb jets this season but did when I first got the boat later in the season last year. They were clear last season. I have since ran a lot of seafoam at different intervals when I first got the boat. Also, did a seafoam run first time this season after sitting through the winter (stored indoors). The flywheel key is not something I have checked to date, so I will add that to my list.

My line of thinking initially for the S.L.O.W mode was just based off these recent alarms and the sudden change in performance wondering if there was some electrical fault that could be causing it to hit a rev limiter or shutting down one bank.

Is it true that a neutral safety switch could cause a rev limiter at 3000 rpm or I have seen some mention a shift interupter switch (all of these are likely on newer vintages of Evinrudes).

For now I will get the compression numbers and repost.

Thanks!
Facts------There is no S.L.O.W. mode on a 1984 model !----Post your compression numbers that you have today.----Then check for spark.-----It must jump a gap of 3/8" or more on each lead.-----Are the 6 high speed jets in the carburetor bowls confirmed to be clean, yes , no or no idea where they are ?----Flywheel key checked ?
 
Joined
Sep 15, 2020
Messages
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One additional item to note that is inaccurate in my original post is that I replaced both power packs not just the starboard side.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,876
The neutral safety switch only prevents the starter motor from cranking if the motor is in gear.-----The neutral safety switch has nothing to to with being a rev limiter.-----Shift interrupt switch in not installed on your motor either.-----You need a manual and need to do some simple trouble shooting.-----Forget hunting on U-tube for a magic cure !!
 
Joined
Sep 15, 2020
Messages
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Fair enough. I will source out a manual for my motor. I was just using the resources I had available to me to find options to explore. Thank you for clarifying the neutral safety switch and for also confirming that my model doesn't have a shift interrupter switch.
The neutral safety switch only prevents the starter motor from cranking if the motor is in gear.-----The neutral safety switch has nothing to to with being a rev limiter.-----Shift interrupt switch in not installed on your motor either.-----You need a manual and need to do some simple trouble shooting.-----Forget hunting on U-tube for a magic cure !!
 
Joined
Sep 15, 2020
Messages
8
Weather was a challenge but I managed to compression test this morning before I left for work. Working from port side down and then starboard side down below are the readings:

P1 - 94 S1 - 93
P2 - 93 S2 - 91
P3 - 92 S3 - 90
 
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