Newbie... Honda 40hp died

jarlarch

Newbie
Jun 5, 2023
12
2
49
montana
Name
joe
Boat Name
Klamath
Hello all I'm new the site and being in Montana we get a late start, I just pulled boats out of storage and went out for a break down float last weekend.

As I noted I have a 40HP Honda, its a 2005 with 2020ish hours. It has run flawlessly till it didn't... here's the scenerio, please help.

Started right up at the dock and motored around for about 10-15 minutes till i settled in and started trolling. It'll typically troll at around 1.8-2.2 mph, in my second pass (15-20 minutes in) I hooked up, first fish of the year (large rainbow), as I scrambled around with the rod the motor died. I didn't think much of it and landed the fish. Ok, back to trolling... nope, the motor would just turn over and over but not fire, i messed with the 'kill switchs' nothing obvious the primer pump n the fuel line was firm so it was getn fuel. I thought maybe it'd gotten flooded so put in the electric trolling motor and continued on. About every half hour i'd try to restart and nothing so headed to the dock (that's when the winds kicked up), no issue just took longer to close the distance but was a reminder of how much of an issue it is to not have main power. Anyway loaded the boat and went home.

I have decent mechanical abilities so started looking at things yesterday but again nothing obvious. Drained the carbs, checked fuses, played with the kill switched and followed the electrical lines. I'm going to check the fuel filter today but it had fuel in the carbs. My gut tells me I bumped one of the kill switches in the controls while scrambling around but I have no idea how to trouble shoot or bypass to check connections. Any help or insight would be appreciated thanks
 
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dwaynesda

dwayne
Apr 27, 2003
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go
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Cabo 216
You have to figure out if it is electrical or fuel related. Normally Hondas are very good on the electric side.

This test will take 2 people. Pull off one of the spark plug wires, insert a phillips screw driver into the spark plug boot and hold the screw driver shaft about 1/16" from the block of the motor and have someone turn the key and see if the spark jumps to the engine block. It should be a loud snap and bright yellow. If there is a spark then it is a fuel issue. If there is no spark, remove the man overboard lanyard and excersize that switch by pulling it out and letting it snap back. Do this multiple times. Pull that little switch out as far as it will go and hold it and try to start the engine again using the screw driver test. Sometimes that switch gets iffy. Most of the time that will cure the spark issue as Honda electronics are generally pretty bullet proof.

The 40 Honda has temperamental carbs with very small idle jet ports that easily plug up. I would bebuild the carbs and use an ultra sonic tank also. This helps tremendously with cleaning out the ports. If I remember correctly, you have to remove the intake manifold to remove the carbs. It is a relatively easy removal.

The gas of today plays hell with small engines. It evaporates and leaves a brown residue that plugs up everything. It is a small engine repair shop full employment act! My guess is that it will be fuel related.

Good luck.

If the motor was running at all, I would have you run a portable tank with SeaFoam in the fuel and let that stuff work its magic.
 
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hbouldin1216

I Should Upgrade My Account
May 10, 2012
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Lodi, CA
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Henry Bouldin
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14 Gregor - Tinacious
That screams fuel issue to me. Honda carbs notoriously bad if you left any fuel at all in the float bowl. Buy a Sierra rebuild kit and do a quick clean. If you have decent mechanical skills, it's a 2 hour job tops the first time you do it.
 
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karlow

Twins 2017
Apr 29, 2004
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karl
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20' skippy Topless /17' whaler Wet Ride (sold) /18' Outrage
Yea but Seafoam eats plastic. Most like it fuel related. maybe some water in there or just some crap.
 
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jigstrike

SCUBA Spearing Daddy
Feb 28, 2004
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Tom McKinney
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Pacific Option, a 2006 Tiara 3000 Open
May not apply but on a tohatsu I had, the in gear protection switch [sobyiu cant start it in gear) failed but could be bypassed easily. Unplug both side of the switch and plug them together.
 
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karlow

Twins 2017
Apr 29, 2004
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Duarte/Covina
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karl
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20' skippy Topless /17' whaler Wet Ride (sold) /18' Outrage
I have used sea foam on a number of small 2 stroke engines. Weed trimmers, chain saws. It eats the plastic fuel lines. I don't know what else it may have an appetite for, but you better have some extra fuel line for your trimmer if you have been using Seafoam!
 
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