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B75 Starting Problems

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tcooke

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"Hay, new here and to smaller

"Hay, new here and to smaller outboards. I have a Honda B75-4011894 and have some questions....

First, what year is this motor?

Second, I am having problems getting the damn thing started, the plugs are getting spark, the timing is set (I believe anyways, dot on cam pulley lined up with dot on bottom of head and "T" line marked with line on flywheel cover) but I don't get any action from the motor. I think it is getting gas as every now and then I get a backfire through the carb.

Does this mean I need to rebuild the carb?

Thanks"
 
Will the spark jump a gap of 5

Will the spark jump a gap of 5/16" on each cylinder-----If it does not you really do not have " good spark " best to check that.------The carburetor does not cause backfire.
 
"I have the BF100, but same Sh

"I have the BF100, but same Shop Manual as BF75 and BF8A and had to guess my s/n by what is seen in that Manual.

The BF75 that you posted about "inverted Air Guide" looks like a s/n between 1,102,881 and 1,199,999 based on type of fuel pump and ignition seen.
This might be early to mid-80's engine, mine is 1,6xx,xxx and was told that it was bought new in 1986.

Thought that the BF75/BF100's were replaced by the BF8A after s/n 1,7xx,xxx (from same manual).

Backfire would point to an out-of-time condition.
(Ignition or Camshaft or both)

I am no expert at all, but think your gaskets should be installed dry or perhaps a little Never-Seize on them,
any 'expert' advice appreciated
"
 
"OK now I am really stumped. I

"OK now I am really stumped. I double checked the spark on the plugs to ground and they arc at least 3/8". The carburator seems to be getting gas through and the cylinders were emptied of any possible extra gas or oil. I used starting fluid to help jump the motor into running.......

Nothing, no combustion whatsoever. I double checked the cam alignment and the "T" lines up with the mark on the housing while the cam dot lines up with the dot stamped on the head.

What are my options?? Anyone know why it wont start? The only thing I can find out of the ordinary is an unconnected blue wire but there doesn't seem to be another end for it.

Suggestions?"
 
"The wire from CDI to Neutral

"The wire from CDI to Neutral Switch is Blue, but if it were not connected, you would have no spark. Other Blue Wires are from Charging Coil to Regulator/Rectifier and is only for Battery Charging output.

If you were able to get it running with starting fluid, then your ignition is not your problem.

Just having gas In the Carburetor is not enough, most common problem is gum/varnish inside jets and passageway's of the carburetor, due to improper storage.

My suggestion would be a complete and thorough cleaning of your carburetor, they don't sell 'kits' but you can get some parts, or complete new carburetors.

Link below is Honda OEM site for CARBURETOR Diagram and parts:


%20JPN,%20VIN%23%20EV4000-100000/CARBURETOR/parts.html,[url]http://www.boats.net/part s/search/Honda/Outboard%20Engine/0/B75K2%20SD%20OUTBOARD%20ENGINE,%20JPN,%20VIN% 23%20EV4000-100000/CARBURETOR/parts.html[/url]

(select your model and s/n range)"
 
"OK here is an update....

I

"OK here is an update....

I spent this evening rebuilding the carb, cleaned out all the jets and passageways and still nothing. I am thinking I have no compression as the engine doesn't ignite at all and when I put my fingers over the plug holes I could barely feel anything. I am going to get my hands on a compression tester and go from there.

Unless anyone knows what the problem might be?"
 
"Check the valve clearance at

"Check the valve clearance at lifters: 0.002-0.004" (0.06-0.10mm)

When you check compression, follow by squirting thick oil in, compression increase points to rings.

Possible Head Gasket problem, or cracks across Both cylinders."
 
"Well after a compression test

"Well after a compression test with 0psi results I double checked the compression guage. All ok on that end.

I removed the head in an effort to find the problem, the gasket, cylinders and head all looks fine. So now I am left with an even bigger mystery.

Tomorrow I am going to check the valve clearance but would that give me a compression test of 0? I think seeing as how the head is off I will give it a top end rebuild and go from there."
 
"If valve clearance is too low

"If valve clearance is too low, it will prevent the valve from seating properly...low or no compression.
Running an engine with insufficient valve clearance can result in a burned valve/valve seat...no compression, even if clearance problem fixed."
 
"Well Thanks to all for your i

"Well Thanks to all for your input.

I have found the problem, both of the intake valve have been bent causing an improper seat and all compression was lost.

Now I just have to find some valves for a 1976!"
 
Carburetor " problems &#34

Carburetor " problems " usually turn out to be something else.You live where in canada?
 
"Bent valves is usually a seco

"Bent valves is usually a secondary failure, i.e., something else went amis first. Better find that other problem before starting engine again."
 
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