1996 P60TL Fuel Enrichment Thermovalve

[MBTundra]

Hello guys, I have a cold start problem with my motor. I?ve flipped thru my service manual (not a factory one) it lead me to the diaphragm which was somewhat distorted so I switched it out and cleaned the circuits and put it back together. It now gets gas thru the grey line when the red switch is on open.

In the normal position there no gas coming from the grey hose. The needle on the valve moves slightly when voltage is hooked directly to it. 4mm fully extended. It?s only moves about a 1mm and the needle seems to be extended a bit when cold, 2.8mm to 3mm.

The manual I have doesn?t have the close and extended valves in it.

After doing my factory approved test by putting my thumb over the hole where the valve is supposed to be and turning the motor over(plug wires off of course) this confirmed that gas was moving thru the grey line when the red lever is in the normal position.

I?m basically wondering if this is my problem and if the valve is serviceable(I doubting it) Personally I think it is my problem.

Some reassurance would be nice before I go drop 200 bills on this part.

I may have rambled a bit but I think I gave a good description of what I did and I think it may help someone else when they look thru the posts.

Cheers and Thanks

Mike

 

[99yam40]

Re: 1996 P60TL Fuel Enrichment Thermovalve

I had a lot of questions on that system also and had others give info also.
You can read that thread and see if it helps any.

http://forums.iboats.com/showthread.php?t=357552


I did do a few sketches of how I thought the passages and flows went and they are in the thread.

 

[MBTundra]

Re: 1996 P60TL Fuel Enrichment Thermovalve

Hey 99 thanks for the link.

I didn't find any of the measurements I was looking for. I did scroll down the screen and find some "related topics" which I read thru as well.

One thing I read that was posted by rodbolt was "its rare they fail."

I'm still wondering, more now, if this is my problem and mine is one of the rare ones out there. I think I have trouble shot this system as much as I could but if it's rare they fail then I'll hope soemone can show/explain me the way!

Cheers

 

[99yam40]

Re: 1996 P60TL Fuel Enrichment Thermovalve

You did get the part that on my motor no liquid fuel flows out the gray hose to the manifold while in the normal position, it is a enriched vapor(mix of air and fuel).
But in the open position there is liquid fuel flow out the hose to manifold.

Explain how you start the motor and what you mean by hard starting cold.

owners manual says not to move fast idle lever, just to turn key for as few seconds and then wait at few and then repeat. If you lift the lever it will cancel the system advance for starting

My manual does not give any measurements either, just make sure it extends after putting 12 v on it for a few minuets.

 

[rodbolt]

Re: 1996 P60TL Fuel Enrichment Thermovalve

if it extends that 129 dollar valve is working.
make sure the diaphram and gaskets are sealing make sure the red lever is in the normal position.
NEVER lift the warm up lever for normal starting.

 

[MBTundra]

Re: 1996 P60TL Fuel Enrichment Thermovalve

Hey guys thanks for the replies.

My motor does not have a fast idle lever, it?s a tiller handle. It?s in the idle position when I try to start.

By hard starting I mean it takes a long time to start. It will turn over and over. Another test I did was a quick shot of gas into #2 on a morning cold start and it fired very quickly.

I?m in Canada, directly above North Dakota and add about 100 miles from the border. So my cold starts for spring and fall fishing are usually only a few degrees above freezing and the highs of the day being in the 40?s maybe 50 if it?s sunny. So you can see why I?m concerned about proper starting.

So I just re-measured the valve cold and it?s 2.7mm. Applied 12v for several minutes and it ended at 3.2mm. So it is definitely extending. What I have noticed now that when cold there is a space (see picture #1) between the round body above the needle and actual grayish ?piston? inside the black housing. The round body and the needle seem to be spring loaded. When pressure is put on the round body, the body and needle move back into the housing. When the valve is cold or hot. See picture #2

Picture #1

Pictures #2

I have confirmed that the red lever is in the normal position. I have confirmed that with the valve in it?s cold state(picture #1) no gas will pulsate out of the grey line no matter how long I crank the motor over.

I have confirmed that with the red lever in the normal position, the valve removed and my thumb in its place gas pulsates almost immediately from the line grey. This tells me the gaskets and diaphragm I put in are sealed and working correctly. This is the same for when the red lever is in the open position.

Rodbolt the part is 200 bucks up here? plus all of our taxes?

So what do you guys think now?

Cheers

 

[seahorse5]

Re: 1996 P60TL Fuel Enrichment Thermovalve

Years back, the old shade-tree fix for a hard starting Prime-start Yamaha was to make sure all the passages and hoses were clear and no varnish or debris was anywhere (same with the carbs).

Take the electric valve and put it in the freezer for a few hours, then remove it and hook it up to a battery for about 10 minutes, then refreezed, then install. Watch the needle movement when heating and cooling. Supposidly the rapid temperature fluctuations helped internally, just like with self-darkening eyeglasses.

 

[99yam40]

Re: 1996 P60TL Fuel Enrichment Thermovalve

like I said before my motor does not have liquid fuel flow through the hose to the manifold while in normal and cold and I have not had anyone tell me that their motor did.
If you do get some to finally come out of yours let me(us) know.

as far as I know these motors are not like the old OMC manual choke systems that fired up on the 1 or 2 pull when really cold, but I never owned a manual start Yamaha with this system on it.

 

[MBTundra]

Re: 1996 P60TL Fuel Enrichment Thermovalve

Seahorse,
I gave it a whirl but no luck. Even frozen, it?s not retracting enough for the round body to clear the passage at the bottom and back of the spot where the valve is supposed to be.

If the Yamaha manual had a minimum retracted length this would solve my question. For the manual to say compare the lengths cold and hot isn?t enough, at least in my opinion.

99,
I mentioned near the end of my last post that raw fuel does come thru the grey line when the lever is in the normal position.

My old motor(Evinrude) was a manual choke and it fired up after 1 or 2 pulls like you say. I have had no experience with a pull start Yamaha either but I guarantee if mine had a pull cord on it right now my right arm would be little use too me. Good thing it?s electric because I?m still able to drink a beer.

Cheers

 

[MBTundra]

Re: 1996 P60TL Fuel Enrichment Thermovalve

Well gents I had a couple of those beers I mentioned and had an idea.

I took a small spring which was able to push back against the round body and hold it up.

I dropped it in the hole, put the valve back in and turned the key.

It fired right up!

So it looks like that my valve is extended to much when it is ?cold?.

It has also has shown that even if the needle is moving the valve may still not be in proper working order.

It seems to me a cold measurement would have been useful is this case.

I?m going to order the part and for what it?s worth I will post the part number and the room temperature length and the length after it has 12v volts supplied to it for several minutes.

It may help someone in the future.


Cheers

Mike

 

[99yam40]

Re: 1996 P60TL Fuel Enrichment Thermovalve

I saw your post,
"I have confirmed that with the red lever in the normal position, the valve removed and my thumb in its place gas pulsates almost immediately from the line grey."
, but when the valve in place does it flow liquid fuel out? How about with the spring in place?

Mine never did and I am not sure if it is suppose to and no one ever posted back if their motor did either. My motor will usually starts on the second 2-3 second turn of the key, but it is not very cold here on the Texas coast and when it is I am not out trying to fish in it.

Check again when you put the new one in place also and please post back with your findings. The measurements with temperature taken and your findings will be good info for me and others.

Post a pic of them side by side if you see a difference in length.

 

[MBTundra]

Re: 1996 P60TL Fuel Enrichment Thermovalve

Well the part came in and it?s the same length so I returned it. So I?m incorrect with this being my problem. I thought I had it figured out.

99, when my valve is in there is no raw fuel coming out of the grey line.

Get this? I wanted to see if there gas was getting pumped into the passage where the valve should so with the valve out I give the key a quick turn.

A small amount of fuel got pumped out and bang!!! It fired up! Needless to say it pumped a lot of fuel out but I quickly shut down the motor.

The things that were different in this situation were obliviously the valve was out, no power to it, also my oil reservoir was moved to the side and the sensor was not grounded.

The previous owner has suspected that the oil sensor was giving him grief.

I was fed up, put everything back together like I was going fishing and tried to fired it up first thing this morning and after 2-5 second(timed) turns of the key.

So I know enough that if the oil sensor gets low it closes a circuit to ground which sends a signal to the CDI and doesn?t allow the motor to go above 2000rpm. Does it change the timing?

Do you guys know if that might be giving me the hard starting problem if the CDI thinks that its low on oil?

 

[99yam40]

Re: 1996 P60TL Fuel Enrichment Thermovalve

Easy to check timing with a timing light while starting to see where it is at.
My 40 CDI adjusts start timing to a few degrees BTDC and then drops back to 7 degrees ATDC once warmed up at idle.
I do not know what yours is suppose to do.

I think the safe mode would limit the timing to limit RPM but that should only affect it if you are trying to go over the 2000RPM

 

[MBTundra]

Re: 1996 P60TL Fuel Enrichment Thermovalve

The timing was a shot in the dark. I figured out what that problem is.

I had the boat out for the first time this weekend and I definitely need to figure out what the problem is.

It doesn?t start up or initially run good at all in the normal position but in the open it fires right up.

The diaphragm is new, it pumps, I can blow down the grey line, fuel can get sucked up the grey line, all the passages are clean.

Is there a passage I?m missing inside the crab? Let say around the float bowl or something like that?

What am I missing?

Cheers

 

[99yam40]

Re: 1996 P60TL Fuel Enrichment Thermovalve

Are you sure you do not have a problem with the carbs pilot jet/passages and it is just seems worse( more noticeable) when cold?

 

[MBTundra]

Re: 1996 P60TL Fuel Enrichment Thermovalve

I?m not sure. What other symptoms would it have? It runs perfect after it warms up.

The previous owner had it at 2 different shops. One place cleaned the carbs and the other said it should be just fine...

After I seen the condition of the diaphragm I changed I?m wondering if the place even cleaned them.

I?m in the same boat as you 99. I would like to know if gas should come thru the grey line in the normal position.

It looks like I?m going after the carbs next.

Thanks