Check engine alarm on Honda 90

dpod2003 · Posted: Thu May 11, 2017 12:34 am Post subject: Check engine alarm on Honda 90

I have owned a 25 Cruiser, with twin Honda 90s for about 5 months. One of the engines has had the Check Engine light and alarm go off 4 times. The engine continues to run fine, even with the alarm on. No sign of any problems. When the alarm goes off, I have shut the engine down and waited a bit. Usually, it runs fine after that, with no warning light. I have talked to my Honda shop, and had a computer check done twice. Nothing has shown up on these.

My question is...has anyone ever had a similar experience? What ideas might you have about this.

Thanks,
Doug Robinson

Grumpy · Posted: Thu May 11, 2017 11:29 am Post subject:

Had a similar situation on twin BF 150's with a solid alarm on one engine. To cut a long story of false computer readouts and much expense involved in getting the boat home, our local friendly Honda guy at EQ had the smart idea of switching the ECU's between engines to see if the fault moved. 15 minute diagnosis and an ECU replaced under warranty.

Might be worth a try.

thataway · Posted: Thu May 11, 2017 12:20 pm Post subject:

It also could be some minor corrosion in the harness or elsewhere--I would pull connections, clean contacts, and put back with some anti corrosive (I use corrosion block spray, a little amount will go a long way...they also make a grease).

Also a loose, or minor in a ground can cause this also...

If it really was a serious engine issue should show up in the computer check...

Grumpy · Posted: Thu May 11, 2017 4:19 pm Post subject:

As always, Dr. Bob is spot on target.

Having spent a lifetime in complex machinery monitoring & diagnostics I can personally attest to the fact that in any electrical system, connections are the prime suspect (add salt water & it get 10x worse) followed by faulty sensors. Or, in the case I quoted you get a really messy situation because many (if not all) the fault codes that the diagnostic computer reads are generated by the ECU (or ECM) and if that has a brain fart, then your codes are garbage and you can end up replacing half the engine if you believe them.

Hence the value of the pragmatic engine tech who simply switches the suspect part to the other engine and sees what happens.

I could have flown that guy up to my boat and paid for a week of fishing for what it cost me before he did the simple thing.

Valuable lesson learned.

Robert H. Wilkinson · Posted: Thu May 11, 2017 9:03 pm Post subject:

dpod2003 · Posted: Sat May 13, 2017 11:28 am Post subject:

Thank you all for the ideas to try on this problem with the Check Engine alarm.

I will start with the simplest, of checking for corrosion and connections, and then maybe try switching the ECU from one engine to the other to see what happens. This is all quite new to me, but I have a service manual and basic mechanic skills with engines, so it is worth a try. Sometimes the technology of these engines scares me off a bit with doing basic work, but the fact that so many C Brats do it helps.

Thanks again,

Doug Robinson

Grumpy · Posted: Sat May 13, 2017 12:13 pm Post subject:

Doug,

From one "Kingfisher" to another:- If all else fails you are not too far from EQ marine in Cornet Bay, home of the "pragmatic" engine guy.

Good luck

Merv

dpod2003 · Posted: Sat May 13, 2017 12:20 pm Post subject:

Merv,
Thanks, and you are correct. We have been there to talk to him about buying boats before, and I was impressed. I didn't realize when you mentioned EQ before, that it was at Cornet Bay. I may follow up with him, too.

Doug