OX66 Alarm Question

[Blaugrana]

I have been going through a few threads with no luck.

My 2000 225 OX66 has the alarm on the oil/ trim gauge go off randomly. The only commonality is that it goes off when in neutral while I am warming up the engine (rarely) and when I am coming back from a trip idling to my dock. I can avoid it going off by getting the RPMs above 700. Thermostats were changed prior to the season.

Has anybody had a similar experience with their OX66?

 

[seasick]

If it is an overheat alarm the common causes are a weak water pump or a stuck open poppet valve.

 

[Blaugrana]

I would like to rule out the water pump as it was replaced earlier this year. Poppet valve wasn’t.

how would I know if it was the poppet valve? Also, what about the oil tank reserve? I thought I read there was one on the engine and curious where it is.

 

[Blaugrana]

One other item to add....I think my oil gauge is off as it always reads as full. I am not sure what is considered as full but the oil tank was halfway filled and then went down to an inch above where the two curves are at the bottom but always read as filled.

since both the overheat alarm and oil are on the same gauge, not sure if they are linked together. No issue with trim though

 

[SkunkBoat]

I have been going through a few threads with no luck.

My 2000 225 OX66 has the alarm on the oil/ trim gauge go off randomly. The only commonality is that it goes off when in neutral while I am warming up the engine (rarely) and when I am coming back from a trip idling to my dock. I can avoid it going off by getting the RPMs above 700. Thermostats were changed prior to the season.

Has anybody had a similar experience with their OX66?

When you say "oil/trim gauge" you mean the Tach?

Are you sure its an oil alarm?

What symbol is flashing?

 

[seasick]

On a 2 stroke there is no oil level indication other than low oil either in main tank (on the motor) or remote tank ( in the locker aft usually).
In general if the water flow is strong (telltale stream) and the motor does not overheat at speed and load but does when idling, that usually points to a bad poppet valve.

 

[Blaugrana]

It’s the tachometer, doing from memory and forgot that’s with the RPMs as well...

I do not think it’s the oil alarm but wondering if something is going on there. It’s the overheating one that is circled. Will periodically flash

 

[Blaugrana]

Ok is the poppet valve an easy replacement? What kind of damage could it cause if not replaced timely? It doesn’t happen all the time

Has anyone replaced theirs recently? I read a few articles on THT and supposedly the orientation of the part changed at some point, giving the impression it’s backwards.

I would like to replace if not major effort. I know how to counter it by increasing RPMs but that alarm is annoying when it does sound

 

[WiltonGrady232]

It's not a hard change, but their will be a moment where you will wish you had a third hand. The rounded end on the poppet valve needs to face inward toward the engine when installing. As an fyi, I've had this happen and even though I thought It was the poppet, it ended up being the impeller. It was only a couple of months old, but had went bad. Sometimes you get a part that was made on Friday afternoon if you get my meaning.

 

[Blaugrana]

It's not a hard change, but their will be a moment where you will wish you had a third hand. The rounded end on the poppet valve needs to face inward toward the engine when installing. As an fyi, I've had this happen and even though I thought It was the poppet, it ended up being the impeller. It was only a couple of months old, but had went bad. Sometimes you get a part that was made on Friday afternoon if you get my meaning.

Haha...That’s my fear. Spent good money doing all the maintenance as if it wasn’t done by previous owner. However, nervous that something was overlooked or just defective.

I’ll take a look at the poppet valve and figure out everything that is needed. Saw people saying don’t just replace but clean inside as well

 

[seasick]

If there is salt buildup in the poppet valve housing, you should clean it as best you can. Replacing is not too bad, just have a copy of the parts diagram to make sure you assemble it correctly. Parts are numbers 21-24 in diagram

Yamaha Outboard Parts by Year 2000 OEM Parts Diagram for Cylinder Crankcase 2 | Boats.net

Buy OEM Parts for Yamaha Outboard Parts by Year 2000 Cylinder Crankcase 2 Diagram

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Try to note orientation of valve parts when removing old one.

 

[SuskyMike]

I just replaced the poppet valve on my '99 225 OX66 a few weeks ago. Replacement was <$30 on ebay, and it took me maybe 30-45 minutes. Like a lot of outboard repair, it's easy in concept, but tough/frustrating while you're doing it because things are hard to reach. My first attempt to put in the new grommet saw it pop thru into the water jacket and drop out of sight, momentarily making me think I'd really screwed the pooch. But I was able to see and retrieve it, and was much more careful w/ second attempt.

A ratchet extension and a flexible u-joint adapter make the bolts easy enough to reach. Tricky part is keeping the gasket/cover/valve all lined up properly while fighting the spring tension when you're reinstalling.

I was having the same symptoms/alarm you are, and the poppet valve fixed it. The old one looked to be in decent shape, but the grommet had some salt/crud build up, and I guess the spring had lost some tension.

 

[Sparkdog118]

Haha...That’s my fear. Spent good money doing all the maintenance as if it wasn’t done by previous owner. However, nervous that something was overlooked or just defective.

I’ll take a look at the poppet valve and figure out everything that is needed. Saw people saying don’t just replace but clean inside as well

some shops try to get by by replacing just the rubber impeller and not changing the whole housing, plate, gaskets etc. If there are any scratches in the lower stainless wear plate, idle water pressure will be down. An easy mistake is to not seat the oring under the housing around the cup. A misalignment will overheat you also.

 

[Sparkdog118]

I just replaced the poppet valve on my '99 225 OX66 a few weeks ago. Replacement was <$30 on ebay, and it took me maybe 30-45 minutes. Like a lot of outboard repair, it's easy in concept, but tough/frustrating while you're doing it because things are hard to reach. My first attempt to put in the new grommet saw it pop thru into the water jacket and drop out of sight, momentarily making me think I'd really screwed the pooch. But I was able to see and retrieve it, and was much more careful w/ second attempt.

A ratchet extension and a flexible u-joint adapter make the bolts easy enough to reach. Tricky part is keeping the gasket/cover/valve all lined up properly while fighting the spring tension when you're reinstalling.

I was having the same symptoms/alarm you are, and the poppet valve fixed it. The old one looked to be in decent shape, but the grommet had some salt/crud build up, and I guess the spring had lost some tension.

The easy way to set the gasket is to apply a layer of 3m 847 between the housing and the gasket and let it dry for about 15 min. You can then install it without any problems. You can use 3m weatherstrip adhesive in a pinch but I prefer 847.
The rubber grommet removal is carefully done with a pair of needle nosed pliers so you don’t drop it behind the exhaust plate. Also installed with the pliers. Lube up the rubber before installation will help.

 

[SuskyMike]

The easy way to set the gasket is to apply a layer of 3m 847 between the housing and the gasket and let it dry for about 15 min. You can then install it without any problems. You can use 3m weatherstrip adhesive in a pinch but I prefer 847.
The rubber grommet removal is carefully done with a pair of needle nosed pliers so you don’t drop it behind the exhaust plate. Also installed with the pliers. Lube up the rubber before installation will help.

Good idea on the adhesive. I know in the past on different motors, I've used a marine grease like 2-4-C to help gaskets "stick" to covers while installing things. But I was hesitant because I didn't have a manual handy and know some gaskets they want you to install dry.

I'm really glad I was able to retrieve the grommet. I've done a fair amount of work on outboards over the years and having turned a minor job into a major one by dropping things into cowlings/jackets before.

 

[Sparkdog118]

I know exactly what you are talking about. Lol. Dry install gaskets are intake and mostly fuel related. Anything with water uses a sealer. 2 stroke head gaskets get perfect seal around the outside of the water jackets and a dry install for the compression ring at the sleeves. I use 847 when I need insurance on a gasket sealing a damaged surface or o rings. Also is good for the outside of oil seals to keep them in place and not leak, especially if the seal housing is scratched or pitted.