1972 mercruiser 165 hp in line 6 cyl

[duffler2000]

this is my first boat a 1972 20' duo vagabond so i dont know that much. i bought it from a guy who got it at an estate auction. it has been sitting for at least 3 years. i went ahead and replaced the plugs wires distributor cap and stern drive along with a new battery i have 2 questions with the boat.<br /><br />1) when i took it on the water for the first time it idles fine until i go open throttle then it just chugs leaving smoke behind it. could this just be a problem with the timing or is it more serious then that<br /><br />2) whenever i hook up the battery my hour gauge clicks constantly shouldnt it only be timing whenever the engine is running. this may be minor but if i dont disconnect the battery it drains. i wouldnt imagine the clock draining the battery what could possibly be doing this?<br /><br />thanks for your help<br /> keith

 

[akriverrat]

Re: 1972 mercruiser 165 hp in line 6 cyl

that long sitting and those symptoms more likely fuel related. was there still any fuel in tank/s? what color smoke? hour meter should only run with key in the run position. might want to check that key switch is actually turning off.

 

[galaxy]

Re: 1972 mercruiser 165 hp in line 6 cyl

You may as well rebuild the carb just to eliminate any further problems with carburetor. Did you check your points? Might want to replace points and set gap correctly. Also check timing while your doing everything else. My 77' 165 is 6 degrees BTDC.

 

[Trent]

Re: 1972 mercruiser 165 hp in line 6 cyl

First.... What color is the smoke? Second... The clock is connected wrong. It should only run when the switch is on. Alot of people hook it to the oil pressure so the clock does not run until the engine is running.

 

[flashback]

Re: 1972 mercruiser 165 hp in line 6 cyl

Those inline 6's are almost indistructable if you take care of them...... listen to Trent and give us a little more info...............

 

[duffler2000]

Re: 1972 mercruiser 165 hp in line 6 cyl

yes there was fuel in it maybe 1.5 gallons i filled it with 93 octane before i went out. i also put a lead substitute in it because the motor decal says it requires leaded gas i also put 1/2 bottle of octane booster in it to try and clean everything up. as far as the carburator is concerned it pretty much looks newer couldnt tell you what kind of work has been done on it though. ponts and gaps were all set when i put the new parts in plugs .035 and points .018 i ws told dwell is 28-34 degrees and timing is 8degrees would it be better to set it on 6. the smoke coming from the back is clear it wasnt black. Thanks for the tip on the clock the hour gauge says 527 that is not all that old then right?

 

[duffler2000]

Re: 1972 mercruiser 165 hp in line 6 cyl

i also wanted to ask because you guys seem to know what your talking about my prob looks old and has a couple of chips in it what size do you reccomend for 20' open bow tri hull

 

[galaxy]

Re: 1972 mercruiser 165 hp in line 6 cyl

What size prop do you have now? I guess that would depend on what your going to be using it for most often. Look on the one you have and see what is stamped on it.

 

[daveswaves]

Re: 1972 mercruiser 165 hp in line 6 cyl

FYI to the 165 chevy 6 users out there. I was having problems with "sand texture grit, very fine" in my fuel bowl that would plug the high speed jets just enough to drop the wot rpm by 400 rpm. The source of the grit was the zinc plating on the accelerator pump spring. This appeared within 20 hours of a carb rebuild. <br /><br />6 deg before tdc is correct as Galaxy notes.<br />As far as prop goes my boat is a 1974 20 foot Calglass, heavy, hard top cuddy,with the same engine. wot is 4000 rpm with 15 pitch prop at 34 miles per hour.<br />Your pitch is marked on the prop, could be a 15, 17 or 19 on there. You need to get your running problems sorted out first and then tune your prop for correct WOT rpm. The correct range for this engine is 3800 to 4200.<br />Your problem definitely sounds fuel related, if the boat sat with the tank low on fuel for 3 years it would definitely get condensation in the fuel, the fuel would be gummy as well and the carb would likely need a kit.

 

[duffler2000]

Re: 1972 mercruiser 165 hp in line 6 cyl

thanks daveswaves i will take the fuel tank apart and clean it out. ill change the fuel filter too and see if that takes care of the problem. thanks for your help ill check back in later.

 

[duffler2000]

Re: 1972 mercruiser 165 hp in line 6 cyl

UPDATE: <br /><br />i filtered out all the fuel changed the filter and checked all the in line screens. i once again fired it up and it sounded great but once it heated up it would start hesitating. i then checked the fuel mixture and re-checked the dwell. i couldnt get the bugs out. my last resort was calling a mechanic that the marina referred me to. When he came by within 30- minutes he told me what was wrong. the impeller was too far goneto pump up enough water to cool off the motor and the garburator needs adjusting. so he said by the end of this week he will be by to replace it nad he said it should run fine. thnks for the help from everyone who led me in the right direction