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BF150 Timing marks

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PaulBF150

Contributing Member
Trying to assure myself that I have the compression stroke. Now with timing cover off I move crank so the marks on the cam sprockets align apposing each other (one at 3 and other at 9) and also pointer on crank aligns with pointer on case (they are situated pointing to the stern), and also have the piston at TDC cylinder 1. I checked the rocker arms (Intake and Exhaust) and they are loose a tad!

I believe that is TDC cylinder 1 on compression stroke??? Do I have it right? How do I differentiate between the compression stroke and the transition between exhaust and intake? I suppose it is the position of rocker arms. Do the other marks align as well?

I did this once before and got it right, but now I am a year older, second guessing myself.

Paul
 
Hi,
I don't know this engine so I'm not familiar with how the timing marks should align but will offer you this:

You are correct to reference the valves.

You can assure yourself that you are on TDC compression by continuing to move the crank in the direction of rotation and observing that the valves remain closed (loose). That will indicate that the engine is on the "power stroke". At the bottom of the power stroke (1/2 revolution), the exhaust valve will begin to open and intake valve will remain closed.

You will need to rotate the crank 2 revolutions from where you began to arrive back at where you started timing wise. It is best NOT to rotate the crank in the opposite direction (backwards) due to possible engine damage from doing so.

It's a tedious exercise but it will give you the answer.

Hope this helps and good luck.
 
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<p>
PaulBF150 said:
Trying to assure myself that I have the compression stroke. Now with timing cover off I move crank so the marks on the cam sprockets align apposing each other (one at 3 and other at 9) and also pointer on crank aligns with pointer on case (they are situated pointing to the stern), and also have the piston at TDC cylinder 1. I checked the rocker arms (Intake and Exhaust) and they are loose a tad! I believe that is TDC cylinder 1 on compression stroke??? Do I have it right? How do I differentiate between the compression stroke and the transition between exhaust and intake? I suppose it is the position of rocker arms. Do the other marks align as well? I did this once before and got it right, but now I am a year older, second guessing myself. Paul
Click to expand...
[FONT="] Suggest you download the BF150 shop manual pdf from readmanuals.com 3-12 costs $14 [URL]https://www.readmanuals.com/outboard.motors/honda/BF135A.BF150A.htm[/URL][/FONT] [FONT="] [/FONT] [FONT="] Section 3-12 will give you instructions for setting up timing chain. the number 1 piston which is the top one is all the way up top of piston is even with head gasket . the crank mark should also now be in correct position. Then go from there with lining up all the timing marks on the cams timing chain and crank shaft. once all marks in place check valve clearance per specs on 3-12 and rotate crank shaft per instruction to adjust remaining valves. when I set the valves on the BF150s its easier to do with exhaust and intake manifolds off more room for the feeler gauged. and I do it to the middle of the specs. I also repeat entire process twice to make sure nothing changed before I put exhaust and intakes back on. [/FONT] [FONT="] </p>
 
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Thank HonDan,

Yup I am working with a hardcopy and computer version of the shop manual. but I might have missed the part on Compression verses exhaust stroke. Yes, I did get the 2 dash marks to align with each other in middle on Cam pulleys and mark on crank with corresponding mark on case (pointing to rear of engine). I could not figure means to align color chain links with dots on cam pulleys. I suppose that shouldn't matter. I guess.

I have another post regarding crank vertical movement or End play, hopefully you could review and answer.

Then still have the Overheat dialog we been having in the private messages. Hopefully you will be able to review and provide recommendations.

Appears you are my only Lifeline in these forums. Otherwise, I'm up the creek without a propeller.

Paul
 
<p>
Vertical movement can't help you on that. My engine corroded out before I got to that level of internal wear. Lining color plates: Ref page 9-11 addresses lining the chain up with the dot punch mark on each cam while the two alignment rectangle marks on the cams are pointing to each other. if your engine ran and you haven't pulled the chain then it is probably lined up as they run link crap or not at all if there off a link. Overheat problem; sheetrock like substance in the thermostat area of timing chain cover not good clean it out along with the sensors with a dremel. and dip thermostats in barnacle buster or pool acid then boil see if they are working. run engine and use temp gun on intake side to get temp readings. Engine and heads usually salt up from the bottom so #4 cyl should be hotter than number 1 if it is blocked up inside. take readings from intake side of engine on block and head. if temp is same or lower on number 4 then passages should be clear. Did you try it with only one thermostat at a time? Try running it with raw water wash down hose (if equipped) attached to the engine flush hose and see if it stops, done this when had water pump go bad and got me home. Could try cleaning vinegar pump into engine thru flush hose let sit overnight, not as strong or damaging as using barnacle buster or pool acid which could eat a hole in the head. If you follow water piss tube back to engine it goes to VST water cooling cover with bunch of phillips head screws on the cover. open that cover up and if its salted up in there good chance engine is also. Can't recommend drilling or rerouting cooling lines.</p>
 
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HonDan,
First of all, HonDan, thank you for responding to my posts and questions.

Appears there are several messages that might be contradicting each other or going backward in the discussion

Current Status: engine open head removed as well as exhaust manifold. Found very little corrosion in water jacket in head or in/around cylinder jugs. Not any hard compacted material as you indicated. Nothing jumped out to explain why overheating. No issue with water pump, plenty of water flow while it was connected as it isn’t now.
I checked water flow into exhaust manifold (2 slots) plenty of water from garden hose. Plugged them off with rag and water started coming out of the block (2 holes at bottom) with no flow restriction.
As to vertical end play, have not observed any metal filings in oil (used vacuum system to pull oil). So unlikely that movement is causing the overheating condition.
Although there were some corrosion in/around cylinders in water jacket area, there still remains sufficient cylinder wall thickness.

Bottom-line: have not observed any water flow restriction or any apparent condition that would justify Overheating, but it does.
Repeating myself the top of the Exhaust manifold gets extremely hot. That is when the boat was in the water. I even went to lengths to spray water on it.
Solution when boat was in the water:

  1. Vent the 2 hoses on top of Exhaust Manifold directly into the water.
  2. Plug off the Over pressure relief valve, not allowing any water to be dumped back into the sea
  3. Installed an Oil Cooler (Sandwich to oil filter with hoses routed to 12x7 cooler, immersed in the water.
This allowed me to get boat up on plane and also enabled the VTEC system to move the secondary rocker arms).
BREAK
Is it possible the Fuel Injector for Cylinder 1 is allowing mixture to run rich causing excessive heat? The O2 Sensor is not causing the ECM to trip any codes, though. I have replaced the plugs, should I replace the Injectors even though they appear to be working, okay? Also, when boat was in water, I did check High pressure fuel pump operation at the fuel test port, but now forgot value, but was sufficient.
 
[FONT=&quot]Block and heads clear of caked in salt thats good news.
[/FONT]


Its not from rich fuel injector. rich mixture makes it cooler lean mixture makes it hotter.
doubt its from 02 sensor when they go the throw alarm.


Its possible too much impellor grease mixed with shells or piece of walmart bag has gone up and clogged the passage way to the exhaust manifold see 19-3 cooling circuit diagram. could try spraying engine foaming degreaser up there and back washing.


I had 09 250 yamaha come from licensed dealer after 300hr service and with one hour trip from the shop to the dock it would over heat over 4000 rpm. owner told take month to get to it didn't want to wait so he asked me look at it. I pulled lower unit found impeller key was not replaced and was on an angle and plate and gaskets were reused because shop could not get old key out. the angle of the key misshaped the impeller and the slight scoring of the plate caused lack of water flow at high RPM. replaced with complete OEM water pump kit all the parts, problem solved.


Think you have a pump issue would replace everything associated with water pump with OEM parts. if that has been done already I would still get an different impellor.
 
In My case the impellor is in good shape. I believe I have it inserted into the sleeve such that the wipers are curved clockwise (as in fig on pg 14-15) viewing from under housing. I replaced the water pump twice with no noticeable difference. Now since you got me to look at the pump, I seemed to of lost the keyway. Plus going to buy another pump so I can check that box.

Any place where water is present it is clear of any junk.

how important is the pressure Relief Valve. Currently I have it disabled as previously mentioned.

A new question, I noticed water coming from the bottom of the case below cylinder #4. I just checked it, and it appears to be a clean round hole. Is that there intentionally? Suppose it provides the water around the cylinder jugs. Whereas the 2 rectangle holes at bottom of sealing surface are the passages for water to get into the head.

Is it correct to have all the block to head water passages closed off by the head gasket?
there are 8 per cylinder. I guess that is way Honda designed it since there is a thermostat for block and another for the head. That is where they wanted the block to run 10 C hotter than head. I think it was for fuel performance. In my case I was not concern with fuel performance right now but preventing engine overheating, thus replaced the 60C thermostat with another 50C one. Plus providing additional oil cooling as well.
 
without the key holding the water pump it will over heat. since your shaft was spinning inside the impellor the center of the impelloer may have gotten hot and damged. without the key it will pump water out the telltail hose. but will not produce enough pressure to keep the engine cool much above idle. Im supprised you got to 4000 rpm before it got hot.
 
HonDan

You can pretty much scratch that thought. I lost the keyway on my driveway while I was removing water pump for inspection.
 
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