looking for a nissan/tohatsu guru

[millacd]

Re: looking for a nissan/tohatsu guru

little update... I found a somewhat significant piece of plastic or epoxy like material in the water passage above marked by the green arrow. It was rounded a little bit, and dimension of about 1 inch by 1/2 inch.

I am not sure if it could be the problem as it didn't seem to be blocking too much of the passage. However, I imagine with water running through it, it could shift positions, and clog up most of the passage.

I tested the riser tube for leaks, it doesn't leak unless it needs to be under significant pressure to leak.

Plan on reassembling Wednesday and testing in a bucket. I'm praying smaller bits of that epoxy aren't clogging and fudging stuff up in the heads.

ADVICE PLEASE:

I took off the outer exhaust cover, and found nothing unexpected except a few broken bolts. They are now removed, but one new hole was not drilled exactly straight.

Should I take off the inner exhaust cover too to be sure there are no clogs? I'm asking because gaskets are backordered into next century, and i'd really not have to deal with figuring out a solution for another one. ALSO, the inner exhaust cover is not exactly forthcoming in removal, and I am very concerned I could break it if I force it any harder. Advice on proceeding? My choice would be to just not bother, put it back together, and run it.

 

[Sea Rider]

Re: looking for a nissan/tohatsu guru

When performing water paths maintenance, all covers must be removed, paths checked and throughout fully cleaned. If engine has a traveling obstruction would be ideal to travel to the thermostat for easy finding and removal. If gaskets are not available, that's other story. Would be a pity to assemble whole engine back to find latter that there's still a hidden clog and in need to go back to page 1...

Happy Boating

 

[millacd]

Re: looking for a nissan/tohatsu guru

we decided to not remove the inner exhaust cover due to the fact we were afraid of potentially breaking it (it was very stuck) and the fact that if after reassembling if there was still flow issues, we could easily take off the outer exhaust cover to access it again to rule out any clogs in there as a last resort.

ADVICE needed:

Should I put silicone sealant on the inside (powerhead is removed still) or wait until it's reassembled, see if it still leaks, and then seal it up from the outside?

Plan for now is putting the powerhead back on at about 7 or 8 pm

 

[Sea Rider]

Re: looking for a nissan/tohatsu guru

You can put a light coat of mega gray engine silicone on both sides of gasket, all related metal parts that seals against gasket should be inmaculate clean and flat prior new gasket installation. Sit head and torque lower bolts well tight, let dry for at least 24 hours. Should't have any water leaks on pan whatsoever, if still with issues, there's someting unusual going on.

Happy Boating

 

[millacd]

Re: looking for a nissan/tohatsu guru

Okay, I need some help.

I got the engine in question back running again. It was a little rough to start, but whatever it started. It idles slightly slower than the engine, so it doesn't really sound sas healthy or "snappy." as the other engine. With the new water pump, and new thermostat, and new powerhead gasket, the stream was SLIGHTLY improved although still not as good as the other engine by a longshot. I supppose the new impeller caused the slight improvement.

Also, I noticed the pee stream warmed up quicker maning the new thermostat is operating properly.

HOWEVER, apparently due to the fact that I cleaned out the hole marked with the red arrow in the picture above (it wsa filled with salt buildup), the leak is now more pronounced than it was before. The new impeller may also be contributing to the increase in flow of the leak.

WHAT THE HECK? I am now pretty pissed. I still have no idea why the water would be designed to enter that area around the driveshaft.

I am fairly mechanically inclined, and I still can't figure out what the heck to do other than pull the powerhead and plug up that little hole marked with the red arrow which is definitely the source of all this water. I say that basically joking out of a lack of other options.


Should my plan be to just put more silicone around the rubber grommet that I've talked about above?

Replace the grommet? (great, I just put the powerhead back on)

Does proper water flow really depend on this rubber grommet to be perfectly seated and sealed?

Should I take it some place? I can't wait around for a shop to play with it. I've been talking to the local Nissan service center pretty regularly about this problem, and they were equally as puzzled and busy, combined with my lack of desire/ability to pay for labor charges, that's why I didn't bring it in in the first place.

I will try to take and post a video of the leak so you people will realize I'm not flipping crazy.

 

[millacd]

Re: looking for a nissan/tohatsu guru

i'm almost tempted to pull the other powerhead so i can figure out what the heck is going on right with that engine, and then make the other engine look exactly like that one on the inside.


Is it possible that maybe that hole is supposed to be plugged by something? The hole marked by the red arrow in the pics above directs water into the cavity where the driveshaft and shock absorbers are. It is interesting to note that this hole is OUTSIDE of the main powerhead gasket. YES, outside. The design, as it appears, looks as if the rubber grommet is supposed to prevent the water from escaping... which seems ridiculous to me. How is a flexible unsealed rubber grommet supposed to stop pressurized water?

Remember, I did find a piece of what appeared to be epoxy sealant within one of the water lines. The water strainer over the water intake appears to be in great condition and probably never removed. This means that this piece of hardened epoxy or plastic must have come from within the water system.

Is it possible that the broken piece of plastic or epoxy sealant was supposed to seal the hole with the red arrow??? That sure would make sense to me.

 

[millacd]

Re: looking for a nissan/tohatsu guru

Is there anything that is unclear in any of my posts? how am I not stopping this leak?

 

[Sea Rider]

Re: looking for a nissan/tohatsu guru

Did you just changed impeller alone or complete water pump kit ? There are some rubber parts that needs to be changed for new ones as old ones will be deformed and not sit or seal well when removed specially if workining in direct contact with heat. Having already seated power head on pan, your last option would be to put silicone around the rubber grommet, let dry and check.

Happy Boating

 

[millacd]

Re: looking for a nissan/tohatsu guru

complete water pump kit. i wouldn't do it halfway after all this trouble. I have put silicone on the rubber grommet.

Is it entirely possible that hole is not supposed to be there? perhaps it wsa made by accident, and then a technician plugged with epoxy as a cheap repair and after 14 years of use, the epoxy finally came loose? I mean, I did find a piece of epoxy in the same water channel that this hole is.

anyone have any pics of the same engine block and same orientation? That could definitely save a debate. I haven't seen any pics or diagrams of the bottom of the powerhead.

 

[millacd]

Re: looking for a nissan/tohatsu guru

update: I have talked to two service centers and one specialist from a tohatsu plant in texas somewhere.

One technician from one service center said that all he can figure to do is plug up that hole, but he wasn't sure if that was the right thing to do.

One service center manager said he would get back to me because he wasn't sure what to do.

Another manager from another service center said he couldn't think of a good reason why water would be designed to come out of that hole marked with the red arrow, and that it would probably be okay to plug it up. He even gave me a couple pieces of metal to try and plug it with. This guy actually had an old 120 powerhead laying around, but it was still attached to the midsection, so I didn't get a chance to peek at it. I have looked at other powerheads (diff manufacturers too), and I have found NONE (out of maybe a half dozen powerheads) that drain water into this same cavity where the shock absorbers are.

This guy also called some people at the tohatsu plant in texas who I spoke to on the phone. The gentleman on the phone seemed very knowledgeable, but I'm not sure where to go from here as some info seemed inconsistent. Apparently, the older 4 cylinder nissan/tohatsu blocks often have this hole in the bottom which apparently serves a dual purpose of draining the powerhead of excess water and "flushing out the area around the shock absorbers of any debris" (I'm not sure how any debris would get there if there wasn't a hole there, but anywho, thats what I was told). On some of the newer blocks including the 115, which is basically an identical block, the hole in question IS NOT there. I was told by the guy on the phone that the people designing the engine decided that it was no longer necessary. He told me that the hole is very normal, and that water leaking out around the grommet is "very common" for these engines. (I have never seen it on any outboard other than this one!). He said that it's possible my other engine is not leaking in the same way either because the hole is blocked up with salt, or that it's entirely possible that the hole IS NOT there, because he did not know when changes were made to the block design to omit that hole, and that changes could have happened mid-year. He recommended to not try to plug up the hole as that's the way it was designed, although identical or very similar blocks DO NOT have this hole. I am very confused as to why some would and others wouldn't have this hole.

The starter just burnt up on this motor, and there was a little bit of leftover moisture in a cylinder probably from spraying/cleaning while the powerhead was off (some may have gone up the exhaust channels) so I have some other fish to fry right now, but who thinks I should plug up this hole?

If I can get the engine running (get the water out of the cylinders) when I get a new starter tomorrow, I guess I will call it okay for now and maybe take the boat out and see if it does temperature-wise. If it does okay, I suppose I could leave it as is for now, but if I continue to have engine tuning problems, I'll take it in, get a service center to fiddle with it.

 

[bcbit01]

Re: looking for a nissan/tohatsu guru

Have I ever mentioned how much I hate saltwater?

 

[comanr]

Re: looking for a nissan/tohatsu guru

check water pump output gromet(seal) and water pipe for corrosion, you may lose water pressure there in the leg.

 

[millacd]

Re: looking for a nissan/tohatsu guru

UPDATE:

I WAS RIGHT ABOUT THE HOLE. The hole was NOT supposed to be there and all other ideas about where my leak was coming from were wrong. it had nothing to do with the water pump, riser tube, gaskets, corrosion, salt buildup, or anything.

I talked to everyone i could possibly talk to, including every local nissan dealer, and including someone at the nissan/tohatsu place in texas. None of the dealers wanted to touch it because they didn't know what was going on with that hole and that's why they referred me to the place in texas to talk on the phone.

The guy on the phone in texas gave me the runaround and said that some of these motors have that hole, and some of them don't, and there is no way to tell which motor years did or did not have the hole that leaked water down into my driveshaft/crankshaft area. He also told me that it's "common" for these motors to leak out the top of their midsection. I personally find that hilarious because on what brand motor is it normal for water to leak out of the area where the driveshaft meets the crankshaft? Really?

I point blank asked the guy if I should plug up the hole with epoxy because of the other motors that don't have the hole. He said he wouldn't recommend it because that's the way the motor was designed (BS).


Well, it turns out I should have listened to my gut instinct because I put the powerhead back together without plugging up the hole as suggested and the extra water running into that area from the hole (extra water because I cleaned the salt out of the hole and water channels) must have traveled up the crankshaft and SEIZED a bearing. Note that above I thought it was the starter that burnt up. It wasn't it the starter, it was a bearing due to water intrusion. Yup, the powerhead is toast.

So I burnt up my powerhead because the design of these motors is apparently for the all aluminum block to be cast with that hole there, and then after the block is cast, it is plugged up with epoxy. How do I know this? because I found a loose piece of epoxy in the water channel right next to this hole. Also, out of damn curiosity, I bought another nissan 120, and ripped the powerhead off of it to see what the heck was going on under there and why mine leaked, and that one doesn't. Sure enough, the hole is there, and it is plugged up with epoxy!!! Must have come that way straight from the factory!!!

I imagine that perhaps that hole is a necessary part of the block casting process and that after the block is cast, it is normally plugged up. Apparently my plug was not a very good one, because I found the piece of epoxy broken loose in a water channel. I understand that this is an older engine, a 1999, and the guy I talked to at Nissan/Tohatsu over in Texas probably didn't even work there at that time, but these same motors were made at least as late as 2005 or 2006, and I'd hope for someone to at least be knowledgeable about some of the details of the block. Unfortunately, not plugging up the mystery hole was the demise of my powerhead and put me out a few thousand. I do like the Nissans and they have performed very well for me up until now, but the lack of technical knowledge about them in local shops, and the difficulty in procuring that knowledge is discouraging me from buying them again. Originally, I was planning on repowering with Nissans when I need to in the future, but I don't know now.