Sudden power loss with prop. or something else??

[primative]

My plan is to take the boat out again with a friend this Sat, and check more specifics.

I was told by my boat dealer (after he asked his mechanic) to disconnect the sensor plug and see if the red light and alarm still goes off. He said he had never seen a heat sensor problem, and his experience of thermostats is that they are more apt to stick in open position than closed. He wondered about the water pump, but I reminded him they changed it in 2003. He was thinking I might be over revving (activating the rev limiter) when I made the sharp turns with my last test run, but I told him it had done the same thing the time before that, at 5400-5500rpm going in a straight path, though there were three people in the boat and gear providing a heavier load. If not over revving he was guessing maybe Electrical module component as next possibility.

I looked at the heat sensor wire and it's fine.

My friend will be bringing a device to get actual water temp when we get shut down-overheat light-alarm. He also mentioned being curious how the sensor relays or receives charge and this might be useful too.

Navicula thanks for your response. I don't know much about motors or mechanics in general but these are my thoughts on it not being a fuel blockage/water problem.
If this was water fuel blockage, the red light that indicates over heating would not be coming on, and my" Racor " view type fuel/water seperator would show water, if it was water. At least when I had some water in the past it showed well.

I'm looking forward to Sat., less talking by me, and more of something else.

tom

[primative]

Went out with two friends on board and it consistently shut down about 5300-5500 rpm. Took temp. near the thermosensor at top cylinder with infrared type point and read gun with temperatures from 202 to 214, but mostly 202 at top and 165 to 175 at bottom. Forgot to disconnect the thermosensor to see if red light/alarm would occur anyway.

Called two differerent mechanics, at honda dealers. One says I'm definately overheating. The other says nah, the top cyclinder runs hotter than the bottom and we ( dealer and mechanic) don't think it's really overheating. When pressed if internal tempuratures are known by them, they do not know.
1-26-05
So I took her out for another test, with the idea of disconnecting the thermosensor for a short period to see if red light/alarmbuzzer would go off. It turns out that I could not create a shut down with the thermosensor connected or disconnected. I ran the motor harder than I did in the 1st trial, but it did'nt matter, no dysfunction occurred.
The tachometer during most of this trial was improper, with readings at W.O.T of 6700 to 6900-7000. When reducing throttle by ear to approx. 3/4 full, the tach. read 6100-6200.When the motor was checked out back in 6-04 at the dealer they made mention in the work order that there was tach. malfunc., but no overheat light/alarm produced. This is the 1st time I had witnessed it myself since their mention of it 6-05. When asking about this recent episode they think it is most likely unrelated to the "shut down to idle episodes".

2-2-05
Bought a new thermosensor at dealership. I installed it and tryed another river test while there. If problem occurred they suggested thier mechanic go out and check for himself ( I was told by feel/experience) if the motor was overheating. It never malfunctioned, and I ran in harder (closer to W.O.T.) than I did in the previous two trials. I shot temperatures again, I guess for the practice of science. The top cylinder 202 to 217 degrees from 4200 to5600 rpm.The bottom cylinder 160 to 178 degrees. Oh ya, the tach. worked fine during this trial.

The dealer said until the problem presents itself more consistently there is nothing they think there is to do at this point.

Want to go out in ocean with me? I did'nt think so. Me neither until problem solved.

tom

[Larry H]

Tom,

Has your thermostat been checked?? Over 200 degrees seems way too hot for an outboard.

You may want to call Les at E Q Marine.

Or, try to talk to a Honda tech rep. Get a dealer to make an appointment or a least a phone conference.

[primative]

Avoided dealing with this, decided to do some fun outfitting. Installed a windless Sprint 600 and Delta anchor with Simpson Lawrence bow roller. Also a motor bracket to keep the 8-horse from dragging and an automatic bilge switch for the rear bilge.

As with all overindulgence, one must come back to reality... the unpredictable but recurring motor overheat-shutdown problem.

I spoke with Less Lampman as Larry suggested. He recommended I inspect the water pump impeller and change it even if it looks OK, and it looked fine. I replaced it.

I took a test run yesterday and within the first mile from the launch it had the sudden loss of power to idle speed with simultaneous red light and alarm buzzer for about two seconds. As soon as the throttle was brought to neutral I am able to take off again to planing speed. The shutdown problem recurred four or five more times over the next few miles, traveling at 4200 rpms. It seemed as if when I kept it at 3900 or below, the problem did not occur.

We checked the windlass several times and it works great. After lunch we hung out at anchor for a couple of hours before returning. On our way back there were no malfunctions, regardless of cruising between 4200 and 5600 rpms.

This problem is running on into many months. I plan next to replace the thermostat even though it opened in a cup of hot water when I checked it earlier. A Honda Service Manager from a dealer on the coast told me today that even if it opens we don't know what temperature it's opening at, or how well. He said my thermostat should open at 155 to 160 degrees. Based on the temperature readings I've been getting at the top cylinder near the thermosensor, 190 - 215 degrees (more often 202 degrees), he thinks I'm running too hot.

I want to say here that at times I can't reproduce the problem by making the motor work harder, i.e. higher rpm's with heaver loads and registering at the higher temperatures.
When the problem is occurring I can't even get it up to the higher rpms because it's already cutting out.

Stay tuned... and as always, your input is welcome.
- Tom

[dogon dory]

Sorry, Folks - Post Deleted By Author

[Redƒox]

[Byrdman]

Hey Red Fox ! Your ears may have been burning over the last week. Your name and some of your photos were discussed during the Nashville Gathering cruise on the upper portions of the Cumberland River System in TN. We got to see a few eagles flying around and checking out our C-Dorys as we made passage up river. New birds to our area and the last time I saw eagles in the wild was the inter passage cruise in your neck of the woods. Wish you could have made the trip Brother! Later

[Redƒox]

Yeah but were there any gorgeous eligible young ladies for me ... Thanx for the notice my friend Can't wait till I get the new Canon 20-D ... waiting

Now, back to the subject here I was also wondering about that water in the 'river' you (CAVU) (if yet talkin to me, that is ) run in. Is it possible that there is a problem with deposit build-up from its water? It does sound like 'overheating' is going on and there is simply an obstruction or leak in the plumbing

[dogon dory]

Sorry, Folks - Post Deleted By Author

[gljjr]

Dan,

I think you are right. This sounds like an electrical/electronic problem. My guess is that it is in the main ignition control box or the wiring to it. That is why you occasionally see the tach way off and why this is so intermittent.

When I was working as a mechanic we had a customer bring in his '73 Mercedes 450SL because it was "acting wierd". In reallity what it was doing was any time you put it in drive and hit a certain RPM the engine would die. Then when it slowed down again it would fire back up. You could drive it at any RPM in reverse though! After many arguments with my boss and many hours of replacing uneeded parts I finally tracked the problem down to a broken wire going to the computer. What was happening was that when the engine RPM's came up the motor moved a little bit causing the wire to lose connection. As soon as the motor shifted back it started running again. I spent well over 40 hours and 5 weeks trying to find this problem as the customer was insistent that we take the time to fix it regardless of what it cost.

To me what you are describing sounds very much like what I had with the 450SL. What I would do is unplug and replug all electrical connections going to the ignition control box. If you find one that looks like it was making a bad connection fix it. If after doing that it still has a problem see if you can find an accomodating person with the same motor as you. Borrow their control box and do a test run. It the problem goes away you have found the problem!

Good luck! These kinds of problems are why I'm bald now!

[tpbrady]

I think electrical is the most likely source of the problem. A key element is the ground side of the circuit. Grounds which change in resistance because they are loose or corroded will change the voltage from a sensor and cause it to read a false positive.

I 1991 Ford Powerstroke that ate about 3 to 5 glow plugs a year. A month before I sold it, I found the problem was a ground wire to the block had a higher than anticipated resistance. The glow plug controller interpreted this a condition that told it to leave the glow plugs on longer than necessary causing them to burn out at a higher than expected rate. All becasue of a few ohms.

[C-WEED]

I think Dan is on the right track. Not knowing a thing about Hondas, I would think a black box is generating the tach signal. The brain senses an overspeed and cuts rpm down. Operator throttles back. Brain senses this and allows rpm to build again as throttle is rolled on. Could be the temp light is another function of the black box? Both over temp and over rev are safety features probably monitored by one box.

The Tach is showing eroniousely high RPM's at times and engine doesn't cut out. Then the opposite happens. Engine is within rpm limit and overspeed cuts in... Find out what electrical gadget deals with both. If it uses a simple sensor under the flywheel or camshaft to sense the rpm check that, too. Possibly dirty from mud-dawber or damaged.

[Redƒox]

LOL I have to agree, after re-reading a little more careful here . But the large temp-variation in the head? taken does not sound normal to me. Could be both, and it comes to a process of elimination, whats another theory going to hurt

[primative]

Hey guys, sorry for the slow response to your replies. I'm illigiterate,and am not too skilletful on the gillternet. I know these are excuses which is a cunning invasion of the facts. So I will try not to be funkey any more, and here it is.

I feel a little giddy.Since I replaced the thermostat I've been out four times without a problem. After reading your responses, I realize it may be a false coincidence, and logically this problem is not likely solved. But if it is that would be ok by me! My wife has intuitively felt it's an electrical problem all along. That doesn't mean anything yet, but we all know its a bad sign.

For what its worth I put the old thermostat in hot water with a cooking/mercury thermometer so I could see when it started to open. I think it started about 172 degrees and was as open as it was going to get at 176-178(I don't know what full open is supposed to look like).I had already installed the new one and didn't think to compare the two.


Looking to the electrical side of things is next. I will let you know what happens.

I really appreciate your responses. These ideas are just what I needed to be able to pursue this any further.

Thanks,
Tom

[dogon dory]

Sorry, Folks - Post Deleted By Author