V4 Looper Cylinder heads warming up at different rates.

[sutor623]

Somebody, anybody........ Should I just pull the starboard cylinder head and see if the gasket is leaking or just go ahead and pull the powerhead? Dont really want to do a rebuild, but this motor is in really good shape otherwise, and I have been looking at the cost of replacing and it is OUTRAGEOUS!!! Especially when you dont know what type of issues you will be looking at getting into with someone elses headache..............

 

[bob johnson]

I am wondering what the desperation is all for.....motors blow up for several reason, usually it is heat...sometimes carbon build up...but it all has signs, and if you monitor your motor. You shouldn't have any issues of blow up... your motor doesn't seem to be self destructing to me.....so it runs a little cool at idle..you could lean it slightly to make you feel better....

most guys would love the "problem" you have over the ones they have....

I wish you the best.....but to rebuild this motor over the problems you have specified is drastic in my view

bob

 

[sutor623]

I am wondering what the desperation is all for.....motors blow up for several reason, usually it is heat...sometimes carbon build up...but it all has signs, and if you monitor your motor. You shouldn't have any issues of blow up... your motor doesn't seem to be self destructing to me.....so it runs a little cool at idle..you could lean it slightly to make you feel better....

most guys would love the "problem" you have over the ones they have....

I wish you the best.....but to rebuild this motor over the problems you have specified is drastic in my view

bob

Thanks Bob, I appreciate the feedback.

I have never had a more tempermental motor in my life on the water. The main issue is that it is very cold natured and often mis-fires at idle upon restarting (after fishing for 30mins or so.) I have to let it warm up for 3-5 mins. before changing spots (plugs are fouled). I am just afraid this annoyance will grow to be something much worse.

I also want to know why cylinder 1 is failing the drop test so poorly. Just cant understand how the motor performs so well in the mid-upper RPM bands, yet is so hard to start when warmer. Some have said that this is due to bad crankcase vacuum/compression, but from what I understand, that will actually cause a lean condition due to the fact that the fuel mixture doesn't get sucked in from the carb at the right ratio. The vacuum at all 4 of these carbs is excellent, and pulling in plenty of fuel.

I just don't understand how one head can operate 20 degrees cooler all day.

 

[bob johnson]

did you ever verify the jet #'s on each carb???...or beyond that, verify the SIZE of the hole in the jet?(people drill out jets all the time!!

bob

 

[sutor623]

Bob,

I did not actually. If I pull the drain screw out the jet sets just behind it, correct?

 

[bob johnson]

that's where the high speed jet is....id also check the low speed needle...make sure it isn't broken off or damaged at the tip.... see if they all look the same...

you are looking for a way that one set of carbs is getting more fuel than the other......... good luck....( ps I don't know why you think the other cylinder isn't just a little hot)

bob

 

[sutor623]

Low speed needles are in great shape. Just looked them all over when I rebuilt the carbs. This thing idles great in gear now that I have it all tuned well. Gotta check the high speed jets when I get a chance, but this still doesnt explain higher idle temps.

I wonder if there is a slight blockage in the port water input line. That bottom cylinder on the port side got up to 175 degree yesterday when I let her run, and the thermostat cover was around 150 degrees. This was after idling in a bucket for 15-20 mins. (Water in bucket was only 60 degrees, as it had fresh well water constantly pumping into it.

Possible that a restriction is forcing more cooling water to the other head opening the poppet sooner.....

Soooooo, another test that I have decided to do is pull the thermostat and replace it with an automotive type freeze plug. This way I can see if the motor isn't warming up because of too much water flow (past the poppet valve) or another issue (too much fuel) I will check the sizes of the jets also. Worth a shot maybe.

 

[bob johnson]

I have had a hot idle bank for 6 years!!! one side will run to 160-180 degrees even in the winter!! while the other side idles at 140-150...once I put some RPMS in her they both drop to the 120's or lower.. yeah id love to know why...but it hasn't hurt the motor that I know of...

I think I have blockage in the water passages somewhere on that one bank.....I try to decarb once a year now.....with seafoam.


bob

 

[sutor623]

I have had a hot idle bank for 6 years!!! one side will run to 160-180 degrees even in the winter!! while the other side idles at 140-150...once I put some RPMS in her they both drop to the 120's or lower.. yeah id love to know why...but it hasn't hurt the motor that I know of...

I think I have blockage in the water passages somewhere on that one bank.....I try to decarb once a year now.....with seafoam.


bob

Wow!! I guess that may just be the nature of the beast?? Yea when those poppet valves open up under pressure things will cool down real quick wont they?!? I have noticed that even the slightest bit of throttle (15-2000rpms) will drop the temp in the heads pretty quickly.

When you remove the spark plugs do the two banks look different? Ever have any hard starting after a good run?I know you told me in another thread, but what motor do you have again?

 

[bob johnson]

I have a 115 ocean runner.. 1995.... I have never had hard starting after the initial start... there were times when it was about 10 degree or colder that I had some starting issues...but once I learned the proper cold weather starting procedure, and have kept two large capacity batteries on board, and I rebuild my starter....zero issues since.....usually I just turn the key and in 2 seconds or less... the motor starts... don't even have to prime!!!


bob

 

[sutor623]

I have a 115 ocean runner.. 1995.... I have never had hard starting after the initial start... there were times when it was about 10 degree or colder that I had some starting issues...but once I learned the proper cold weather starting procedure, and have kept two large capacity batteries on board, and I rebuild my starter....zero issues since.....usually I just turn the key and in 2 seconds or less... the motor starts... don't even have to prime!!!


bob

Thats awesome! Wish I could say the same........... But we'll get there, wont we???

 

[sutor623]

Good news and bad news..............

So I found out why my heads werent operating at the same temp. There was a minor water blockage coming into the port head. I blew it out with high pressure from the waterhose and VOILA!!! Both heads now stay within 5 degrees of each other.

Heres the issue though. This motor has always been tough to start and warm up, so I figured this would have helped with this issue, and it did to some degree, but even at operating temp, the motor still failed the cylinder drop test ( #1) pretty badly. I was just going to leave it alone and take it to the water, but it would NOT start up in the cold. Not even try to............ SO I said to hell with it and pulled the starboard cylinder head and here is what I found...........





Buttttttt, does this look like water intrusion to you???



Look how clean top cylinder head is.

 

[bob johnson]

well, I would guess, a nice clean up of the head and a new gasket, and you would be looking good.... bob

 

[sutor623]

well, I would guess, a nice clean up of the head and a new gasket, and you would be looking good.... bob

Thanks bob I'll let us know how it goes. Hate it when people don't conclude their threads with the results.....

 

[kenmyfam]

Did anyone suggest or did you do a decarb on this motor. I did notice earlier on you said it had spent most of it's life at idle speeds.

 

[sutor623]

Kenny, I tried to do a decarb with no success on hat head because it was running so cool. Should I clean it up before I put the head back on?

 

[bob johnson]

I know you already have the motor apart...but I just got my 1997 175 fatstrike running this past weekend out on the water! The motor would not warm up and the tell tale was SUPER weak....but the temps didn't budge the gauges....I ran the boat any way and couldn't get even 10 psi water pressure... so I checked to see if the motor even had t stats...sure enough it didn't!!.....so my t stats are supposed to be a white plastic or ceramic cone shaped thing...and it is held under spring pressure to a seat in the head. I HAD some at home and installed them and sure enough one head warmed up, but the other didn't!!! I pulled them again, and I think the reason is the seat isn't perfectly round...thus water gets by...even though the t stats didn't open!!! and that head never warms up enough to let water flow full bore into the head... I wonder if that was possibly an issue with your motor as well....one head was warm the other was too cold.....right??? how is that?? well I just found out how it could be on my motor!!!

bob

 

[sutor623]

I know you already have the motor apart...but I just got my 1997 175 fatstrike running this past weekend out on the water! The motor would not warm up and the tell tale was SUPER weak....but the temps didn't budge the gauges....I ran the boat any way and couldn't get even 10 psi water pressure... so I checked to see if the motor even had t stats...sure enough it didn't!!.....so my t stats are supposed to be a white plastic or ceramic cone shaped thing...and it is held under spring pressure to a seat in the head. I HAD some at home and installed them and sure enough one head warmed up, but the other didn't!!! I pulled them again, and I think the reason is the seat isn't perfectly round...thus water gets by...even though the t stats didn't open!!! and that head never warms up enough to let water flow full bore into the head... I wonder if that was possibly an issue with your motor as well....one head was warm the other was too cold.....right??? how is that?? well I just found out how it could be on my motor!!!

bob

Yes, VERY frustrating to say the least. Make sure that your relief springs are fresh. Another odd thing that I noticed is that taking the therm out and putting it back in sometimes did the trick, and then it seemed to surface again. I think you are correct, the seat in the heads are flawed.

There is a very small hole at the bottom of the head just under the bottom cylinder that can get plugged up. It is about 1/4" so can get plugged easily. Very annoying.