87 blackmax 175 help

jigmister

Petty Officer 1st Class
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Dec 25, 2007
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203
well guys my 87 black max 175 HP is not healthy anymore.

since about last spring its been acting up a bit. every once in a while at blast off it has had no power. Put the hammer down on the throtle and it would just bog.
Slowley but surley she would build up some power and get on plane. after a little bit of this she would take off like a rocket and run like a champ the rest of the day.
Never miss a beat for many trips.
Then this problem would show its face again and go away just as fast.
I just figured it needed to be run to blow the carbon out or whatever.

well today that problem showed up and did not go away. In fact became worse.
she never got past about 3,500 RPM. when shes right I run 5,000 and capable of about 6000
So 3,500 was all I could get. So I drove it at that for a few miles. Then for the first time the spuddering and coughing began. Jugging and spiting.
Nursed her home on idle.
what do you guys think? sound fuel related?
could it be a switch box? Stator? Coils?
I took the carbs apart this afternoon and cleaned em out. found some debries in the fuel filter at the fuel pump.
have not had a chance to put her on the water yet after the cleaning

any clues?
 

SparkieBoat

Captain
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Aug 17, 2009
Messages
3,643
Re: 87 blackmax 175 help

when ever you notice a problem with your motor it is NEVER because it needs to be run and blow the carbon out..it is almost always a mechanical/electrical/fuel problem that needs immediate attention. if it is a partially clogged carb then you have been running a lean cylinder and may have already burnt a piston up. first thing to do is compression check..then spark test with a spark gap tester,. then check carbs/fuel lines and connections...then break out the dva adapter and start testing stator, switch boxes and coils. new plugs are always a good idea.
 

jigmister

Petty Officer 1st Class
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Dec 25, 2007
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203
Re: 87 blackmax 175 help

I sure hope I did not melt a piston.
what is a DVA adapter? I can use a fluke multi meter to measure ohms.
same differnce?

also I should mention the fuel pump. I preformed the test per the book.
disconnected the fuel line at the top carb. squeezed the primer bulb and got a nice healthy stream of fuel. the stream was the same dia. as the hose.
then cranked the the motor and the stream was not nearly as healthy but consitanly the same. about half the dia. the hose.
unsure if that is good or not.
got a pump kit on order anyway
 

Superjetjim

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Jun 5, 2010
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217
Re: 87 blackmax 175 help

Have to admit I was cringing reading this post - sound like fuel starvation, hopefully you haven't seized a pot but wouldn't be surprised if you had to be honest. It was most probably a minor blockage floating around in one or more of your carbs hence the intermittent nature (part blocking jets) a fuel pump rebuild should be done as well - cost is very minor and takes 20 mins.

It's been said now - but NEVER run an engine that doesn't sound right or hardens off/changes RPM during use, kill the power and check into it - only exception is life and limb.

Good luck and I hope it's ok

Jim

Do a compression test - if all are equal you may be OK.
 

SparkieBoat

Captain
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Aug 17, 2009
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3,643
Re: 87 blackmax 175 help

a DVA adapter can be used WITH your fluke meter to measure direct voltage on your outboard. CDI electronics web site has comprehensive diagnostic instructions...if you are going to be a DIYer get one..$25 plus shipping and well worth it. http://www.americastoolwarehouse.com/automotive-tools/ESI-640.html fuel pump sounds like it needed rebuild/replace. but it could also be a connection or crack in fuel line allowing air into it..remember your fuel pump sucks not pushes the fuel..so a fuel line leak will not leak fuel it will suck air into the line reducing/stopping the fuel flow.
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: 87 blackmax 175 help

remember your fuel pump sucks not pushes the fuel..so a fuel line leak will not leak fuel it will suck air into the line reducing/stopping the fuel flow.

Usually just before a piston melts.
 

shouldBeFishin

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Feb 14, 2011
Messages
3
Re: 87 blackmax 175 help

I had a similar problem on my '86 Black Max 150. The switchbox(es) were bad, and eventually the stator went. All of this nickle and dimed me over a year's period of trial and error and a lot of frustration. Now that both switchboxes and the stator have been replaced, it runs perfectly. My research found that the better mechanics recommend replacing both switchboxes at the same time.
 

jigmister

Petty Officer 1st Class
Joined
Dec 25, 2007
Messages
203
Re: 87 blackmax 175 help

Tested compression few minutes ago. all 6 holes are between 120 and 122

books tells me to ohm out the stator and switch boxes

what do you guys say?
hope I did not ruin this motor.
 

jigmister

Petty Officer 1st Class
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Dec 25, 2007
Messages
203
Re: 87 blackmax 175 help

what dose a DVA adapter let me measure? I am lost here. I know how to use a mulitmeter, amp clamp check uf and ohm out windings.
this DVA is brand new to me. Interested but lost
Also are you saying I can not properly diagnose the problem via the book
 
Last edited:

SparkieBoat

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Re: 87 blackmax 175 help

it allows you to test the direct voltage coming from/going to your stator, power pack, rectifier/regulator and coils. all you do is plug it into your multi meter...be sure the positive and negative go into the proper slot. the CDI site will tell you exactly which wires to test. some test will be while cranking, these can be done with plugs out and you touch the leads to the wires specified, other test are while running, this will require you to pierce the wire insulation with the pointy probe, be careful to not break the wire and seal with liquid electrical tape when you are done. be sure to pay attention of how to test, you do not always ground the negative, like in the stator test you touch one lead to the brown and the other to the brown/black..not the engine ground. it can be tricky to do this in the connection with out crossing the probes, I had a old power pack laying around and made me a test harness..made it easier...you sound like you will get the hang of it quickly...just post any questions, also CDI has a great customer support staff, more than willing to answer any questions..which is 1 reason why I purchase CDI replacement parts for all my motors.
 

SparkieBoat

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Re: 87 blackmax 175 help

I have found OHM testing stators to be not the most reliable way to test them..but you can give it a try
 

jigmister

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Re: 87 blackmax 175 help

ok so the DVA adapter you linked is compadible with my fluke multimeter. Sounds like it is with any meter.
I will order that.
in the mean time I will sit up tonight and search out instruction at CDI.
are they instructions specific to my motor or same for all?
 

SparkieBoat

Captain
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Aug 17, 2009
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3,643
Re: 87 blackmax 175 help

yes specific test for your motor...also if you look up your part numbers and find the corresponding CDI part then you can download the install sheet which has specific test for each part.
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: 87 blackmax 175 help

What a DVA adapter does is store and hold the peak voltage. In electronics parlance it is an integrator circuit. Any meter will measure it's output, with the caveat that the meter sensitivity is high enough to not significantly drain down the DVA adapter between measured pulses. In other words, any quality meter will work.
 

jigmister

Petty Officer 1st Class
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Dec 25, 2007
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Re: 87 blackmax 175 help

ok I will give her a shot. I will have questions. In your opinion are there any parts that I should replace reguardless? switchboxes coils stator or?
 

jigmister

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203
Re: 87 blackmax 175 help

one other thing just came to mind that I noticed. at idle in N the tack reads about 800 or so. then when I drop it into gear to idle out the no wake zone the tack jumps to about 1,300. You can clearly hear that the RPM did not increase.
Never use to do this before.
May this be a clue to the over all problem??
 

CharlieB

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Apr 10, 2007
Messages
5,617
Re: 87 blackmax 175 help

I know how to use a mulitmeter, amp clamp check uf and ohm out windings.
this DVA is brand new to me. Interested but lost
Also are you saying I can not properly diagnose the problem via the book

If you understand that an 'amp clamp' measures current flow, an AC circuit can have voltage but with a poor connection will NOT carry the amps/load, then the DVA is sort of a comparable test of voltage on a LOADED circuit and will show LOW voltage (voltage drop) on a poor circuit.

CDI Electronics has literally 'written' the 'Book', a VERY detailed Outboard Ignition Troubleshooting Guide, available for free download, get it.
 

SparkieBoat

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Re: 87 blackmax 175 help

I should get a job with CDI as a rep..I really like how they have made better after market parts along with better customer support and better prices when compared to the original manufacturer...they have earned my business and respect. wonder if they sell stock??
 

jigmister

Petty Officer 1st Class
Joined
Dec 25, 2007
Messages
203
Re: 87 blackmax 175 help

ok I ordered the DVA. I was reading the insturctions at CDI on testing some of the components.
It appears that many of the test preformed with the DVA require the engine to be a WOT. Without a water tank how dose one do that?
Laying on the stern at 60MPH???
I did not see the "book" I will look for it. if you get a chance link it here Thanks.
I really appreciate all the help
 
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