Black max 200 help

[Jessica.c]

Hello everyone, my name is Jessica and I am new to the forum. I signed up because my husband and I have been trying to work the bugs out of our 1986 mercury black max and are still having an issue. The darn thing will not run at the lake! Since buying it my husband has rebuilt the fuel pump, carbs, done a compression test, changed the water fuel separator, synced the carbs and timed the motor. It runs fine on the fake a lake and also in a 70 gallon tub we bought but as soon as we go to the lake it just won't stay running. Any suggestions would be greatly appreciated I am at the end of my rope with this darn thing, I have read the seloc manual and can't think of anything else it could be. We are fairly certain the vent isn't clogged and we have brand new gas and oil in it. Thank you in advance for any advice, I am thinking our next step would be to maybe check the reeds or maybe it's over oiling but thought to ask here first.

 

[Jessica.c]

OK so after posting this my husband and I went out and took the lower unit off to check the gaskets and the oil to be sure that water hadn't been leaking into it. It's one of the only things we hadn't done since the mechanic we bought it from said he just serviced it and put new oil into it. Low and behold the drive shaft is siezed up and their is no oil in the lower unit! Luckily we have another one that my husband can rebuild, so my question now is, could this issue have caused it to not start at the lake?

 

[rjcamel2355]

It would probably still "start" in neutral, but I imagine once you put it in forward or reverse it would have made all kinds of racket/died or not went anywhere if it's seized up.

Do you have the compression #'s? so we can see what they are?
Vent shouldn't affect starting/idling, but would affect your top end/acceleration.
I could be wrong here, but most of the ones I have seen not run under a load (at the lake) was usually carbs or compression related.... just my experience.

I've got the same motor sitting on my boat, and I'll try to help ya out where I can, but there are definitely far more knowledgeable folks on here that will also chime in and help I'm sure.

 

[Faztbullet]

If driveshaft was seized the motor would not turn over......

 

[Dukedog]

what faz says... and

trash tha seloc (way to generic) and get tha oem for your motor.. won't run under a load can be any one or a combination of comp, fuel or electric.. tha oem manual will cover testin' tha parts.....plus ya might find another mechanic if ya thinkin' 'bout usin' tha one that sold ya tha motor..............jmo

 

[Jessica.c]

So the compression was all between 138 and 148 across the board, there is definitely spark and the carbs just got rebuilt and synced. The seloc manuals drives me crazy nothing is where it should be so I will look into the oem book I didn't know one existed so thank you for that info. I am trying to find another mechanic in the Sacramento area that will work on the older outboard since there is nobody around our area and it's the closest major city!

 

[Chris1956]

I would concentrate on the link and synch for the spark advance and carbs. Do your carbs have adjustment screws for the idle mixture? A lot of the early V6 motors had fixed idle jets. Those carbs need to be spotless to have the correct idle mixture.

 

[Jessica.c]

There is no adjustment screws in the carbs. As far as the link and sync goes we followed the seloc manual which was pretty confusing, can you give me maybe a better source to use online or a step by step on how to do the link and sync? My husband doesn't think that is the issue because it runs at home and in the tank but I am open to anything at this point. Also we were talking today about the jets and maybe they aren't the proper jets for our elevation. My husband said we need jets that would be for sea level since we live in the valley. I have searched and searched for a chart with the specs for the wh31 carbs and have yet to find one. We have been buying the parts for our boat from a boat shop that said it should be the same as the WH28 which is what apparently came on the boat. The jets currently in the boat are 0.56 for the Idle jets, 0.96 for the vent jets, and 0.76 on the top 2 carbs and 0.78 on the bottom for the main jets. That is what the boat shop said to use but as I said it was what was recommended for the WH28. Which leads me to another question what exactly is the difference between the two? Sorry to have so many questions I am just trying to figure out what is wrong with it so we can go fishing! We have been at it for almost 3 months now. The boat shops we talked to today said they are book through October and I am hoping to not have to wait that long to get out on the water, the darn Salmon are here and were gonna totally miss the season. Thanks again for all the help guys I really appreciate it!

 

[Faztbullet]

STOP!!!!!!! Don't do anything till you get a factory manual!!!!!! Already the main jets are in wrong locations as the 78's go in cylinder 2 and 5

 

[Jessica.c]

So just wanted to post an update, after my last post I actually spoke to a tech at Mercury and he gave me all the specs I needed. We rebuilt the water pump and filled the lower unit with Mercury sae 90 gear oil reattached it. After starting the boat in the 70 gal tank and getting it warmed up we ran a gallon of gas with premixed oil and a can of sea foam (recommended by mercury tech) through it engine. Today we took it to the lake and it started right up and we drove it around for about 30 min with no issues. The tech said that it sounded to him like the little holes in the middle section that let the exhaust out were clogged. So when the lower unit filled with water it couldn't run. The sea foam steamed the excess carbin out and now it seems to be fine. Thanks for all the help and if there are more issues I will let yall know!

 

[Chris1956]

Gee, I never thought the exhaust relief ports could get clogged. I am glad it is running for you....

 

[bajaunderground]

---

I just removed mine...made it louder...that's about it!

 

[Chris1956]

Baja - Exhaust relief ports are cast holes in the midsection, just under the powerhead. Not sure how one would remove them!

 

[Jessica.c]

OK guys so update, we took the boat out to clear lake over the weekend and once it started it ran great, but we stopped to fish for a bit and had trouble getting it restarted, once restarted it ran great again. Then we stopped to fish and the same thing happened! Any ideas on what to do next? Also my husband decided to recheck the timing and this is probably a dumb question but when the #1 piston is at top dead center what number should the timing pointer on the flywheel cover be pointing at? I have the dumb seloc manual and photos of the factory manual timing and carb sync pages but am still confused. Thanks for the help

 

[Chris1956]

Obviously, when the top piston (make sure it is the top one), the timing cover pointer should indicate TDC or very close. There is some "play or error" in the piston timing as it comes to TDC, so the timing mark may be off a degree or two. When you set the timing pointer to .464" before TDC, you are attempting to reduce that error.

 

[Jessica.c]

So on my flywheel that .462 mark is like 2 inches away from the 0 mark and it's not even in the little window.

 

[sam am I]

Stroke of the piston is 2.650"

The crank rotates 180 degrees (probably more like 200 from over the hump dead spots) to move the piston this 2.650"

2.650"/180 degree = 0.0147"/degree

0.462" is the distance/setting the piston moves down/away from TDC/0 when setting up the timer pointer, then

(0.462") / (0.0147"/degree) = 31.38 degrees, this is the rotation in degrees of the flywheel from the TDC/0 to the 0.462" mark

The flywheel is 12" diameter (I think)

Arc length S = (31.38/360) * (pi*12") = 3.29", this is the linear distance the TDC/0 mark is from the 0.462" mark. Give or take

Yes, the "0" mark should be out of the window somewhat with the pointer on the "0.462" mark.