155 oil change

[evb11]

Im ready to do an oil change on my 67-68 johnson- Any best practices here? I was thinking i would plumb a flexible tube from the drain plug and out the bilge drain. Perhaps get the engine heated up before i drain? What sort of oil would anyone recommended for peak performance? I have just done plugs and wires, although for some reason the coil to cap wire wouldn't conduct spark, so i just put the old one back on...

Also, just any other tune up recommendations for good performance would be great. Im still just getting used to piston engines!

[bchowk]

Sounds like you are on the right track to me....Flexible tube for the oil change is a good idea, some of the folks here have installed valves in place of their drain plugs so that the oil change is a much simpler and cleaner process.

As far as oil change or tune up goes, I tend to take the approach that these 155 v6's are really just JEEP motors with marine parts on them. For oil I just use a nice quality 10/ w30 and a can of engine restore (I have the origional motor in mine) If yours is the boat I think it is you have a 231 even fire, don't you?

Anyway, fresh plugs and wires (great), oil change (your on it), maybe a new fuel filter/ water separator ( I change mine about every other year), Check and set your timing (mine LOVES this), adjust your carburetor idle mixture, adjust your idle speed then repeat til everything is just right and she'll run like a treat.

I use a vacuum guage to set my idle mixture...it really takes the guess work out of adjusting the carb. Like I mentioned earlier, using the vacuum guage, I set the timing to 6 degrees BTC, set the idle speed (on the linkage port side of carb) to about 750-800 RPM, adjust the idle mixture screws (one at a time) till they are at max vacuum (first peak), then check everything again and adjust until all those parameters are within spec....then enjoy your smooth running boat!

Here is a link that talks about general automotive tuning with the vacuum guage...this directly translated to tuning your boat (for the most part) you will not have a vacuum advance or a brake booster
http://www.tuningmadeeasy.com/tuning/va ... nder-tool/

Cheers,
B.C.

[JimAndros]

What sort of oil would anyone recommended for peak performance?

The oil currently recommended and marketed by BRP (was OMC) is straight 30 weight.

MerCruiser recommends and markets 15W-40.

Go figure which is better. I use the OMC oil.

[evb11]

BC- Thanks for that link! Although i might be more confused now after reading it!

I get the timing ( using the timing light )
The vacuum gauge and setting the idle mix screws seem easy enough

Then they start talking about a bunch of other stuff:
# Dwell angle
# Vacuum advance
# Centrifugal advance
# Advance curve
# Float level
# Power valve
# Accelerator pump
# Secondaries
# Jets

If my engine runs pretty good already- should i be paying attention to this stuff? It seems like a lot of these are based on buying aftermarket parts, or disassembly of the carb.

Other topic, reading about the Choke settings, made me think if that's what is causing the engine to have cold start issues. AKA, it doesn't want to start cold without a squirt of starter fluid. I think that this carb may be of automotive make, but not sure. Either way i believe its an electric choke, seeing as there's a electrical spade terminal sitting empty on the choke housing. Forgive my ignorance in all of this, but if it IS an electrical choke and it wasn't getting 12v- would it cause a super lean scenario and make it difficult to start?

Also, i can find Lee's engine model # page any more- It was linked in my other thread, but has since disappeared with about half my original post.. hm- weird!

[Peter_Crowl]

Hi Grae,
Your initial - in depth - post was in the Marina Section viewtopic.php?f=17&t=222 and seems to have everything there. I say In Depth as you also posted a short intro in the Intro forum.
If something is missing please let me know as I didn't touch a thing. Truth is I don't know how - yet. There's a lot to learn about running a forum :~)

Lee has given me permission to use material from his site. I just put his model number chart in the forum in the Restoration Resources section.. viewtopic.php?f=24&t=231

It's a quick and dirty data dump that I'll make pretty in a bit as I work on the Website pages.

Hope this helps!

Peter

[evb11]

Peter- I was mistaken- I got all that info from the email postings- I went back and found it- Sorry!

[evb11]

I can feel where the oil drain plug is- This seems daunting. I could conceivably get the plug out, but then what? seems like the oil would just make a huge mess as there is no real bilge or space to put a drain pan.

Also- Before i do anything smart: ? the other end bolts to the block- i assume its a ground

[JimAndros]

The 2 small terminals on the solenoid are the control circuit. Power in on the tan wire, thru the coil & out to ground thru the black wire. Doesn't matter which wire goes where.

As for the choke. You have an electic heat connection on the spring housing. With the engine cold & no power applied to the spring, adjust the spring by rotating it until the choke just closes.

When you start the engine, the choke pull-off should pull the choke open enough to keep the engine running while the choke heats up & opens on its own.

[Peter_Crowl]

To address your oil change issue - the way most handle it is to use a hand pump to extract the oil via the dipstick tube.
Here's a good pump from West Marine -
http://www.westmarine.com/webapp/wcs/st ... sNum=10440

It gets good reviews...I have one but haven't tried it as of yet.

Peter

[bchowk]

OK so for the other stuff....

Dwell angle is your points (can't help much here, I converted to a pertronix kit and never looked back)

vacuum advance- this is a car thing if you had one I believe most boat people would tell you not to use it (a vacuum advance unit will look like a metal cone on your distributor with a hose connected to it)

cetrifugal advance- you have this, and is simply springs and weights that advance your timing as you get higher RPM (check it out, after you have set your timing at IDLE to 6 degrees check it again at, say 1200-1500 RPM your timing should have advanced) If you wanted to modify your advance curve you can change the springs for a quicker or slower advance

Advance curve- refers to combination of said vacum and mechanical advance and is the amount of advance at given RPM plotted on a curve (I wouldn't worry about this if your just trying to tune up your boat but if you get into modifying for performance, is something to read about, lot's of opinions out there)

Float level- there is a float that stops gas from pumping into your carb when the bowl is full, how to set that depends on the carb you have (wouldn't worry about it unless you are flooding or cutting out at high RPM)

Accelerator pump, power valve, secondaries and jets are all about how you set up or tweak your carburetor if you are rebuilding one (if your running pretty well I wouldn't worry much about them, again if your looking at upgrading for performance, take a look around at what the jeep or buick hot rodders are doing, read up on carbs. some neat stuff out there, we just need to be careful about remembering we are talking about marine applications....

Did a little reading on the choke...soooo inside that little metal can is a bi-metal spring that will open up the choke plate as it gets hot. the 12VDC spade on there connects to a little heater element that heats the spring....soooo when the boat is COLD the spring closes the choke, letting in less air and making you mixture "rich" as the spring warms up the choke plate open letting in more air "leaning" the mixture for normal running...I used to have to really pump my old carb quite a bit until everything was primed and warm...if your having an issue with cold starts, try cranking the engine a bit (to make sure you have fuel in the lines and filled the float bowl, then pump the throttle a dozen or more times then try it (i used to pump mine about 30 times before lighting it off)... hope this helps

Cheers,
B.C.