Newbie Help

[Rosati]

Hi. <br />I've been reading these forums for a couple of weeks now trying to fix a friends motor he bought used an not running. He has a 1985 Johnson 150 20" shaft electric start, T&T. I have replaced the cables and fired it up on the hose and it ran great. Took it to the lake and it stumbles off idle while trying to plane. I have since learned that the carbs need cleaned out and I have them soaking right now.<br />The qestions I have are basic but I cannot seem to find them in the thosands of posts here.<br />1. What is the difference between a looper and a crossflow? Is it the style of manifold or what?<br />2. What range of V6 engines are similar to the 150 I'm working on? (example, 305,327, and 350 cid GM car motors are all similar with differences in bore, stroke, etc)<br />3. When driving the boat, should the motor be trimmed all the way down to get on plane then trimmed out to raise the bow or should a sweet spot be found and left there? <br />BTW, we are using a 14 1/2 x 19 3 blade aluminum prop on a 1986 Ranger bass boat.<br /><br />I have more questions to confirm what I have already done, but will wait to keep this short.<br />Thanks in advance.

 

[llfish]

Re: Newbie Help

What RPMs are you turning at wide open throttle.<br /><br />The first thing you may want to do is some preventive maintenance things. Decarb the engine, change water pump and gear case oil. Then move on to getting the engine running correctly. When that is all done you can work on the plane. That will require taking detailed notes as to rpm, mph, trim positions and time it takes to get on plain. Once you find the best setting leave it there. Only change one variable at a time.

 

[Rosati]

Re: Newbie Help

Here's what I have done since I first started with this motor:<br />1. Pulled float bowls and cleaned them out<br />2. Changed spark plugs with champions (plugs have no bridge to gap)<br />3. Removed old fuel lines and replaced with new<br />4. Removed and cleaned fuel filter an installed another automotive style inline between bulb and motor<br />5. Replaced fuse near starter motor (would not turn over with key, found fuse after going through entire wiring harness)<br />6. Replaced prop as old 13 1/4 x 27 SS 4 blade appeared to be bent (will send out for repair later) with 14 1/2 x 19 aluminum 3 blade.<br />7. Drained lower unit and filled with fresh lube (no water in old lube but only 1/2 full)<br />8. Replaced both cables because one was broken and other was split<br />9. Hooked up to hose (cracked open the valve so as not to force water into engine and slowly increased to maintian supply) and tested in driveway. Forward and reverse working, no fluid leaks.<br />10. Removed VRO and oil tank and mixed 12 gallons of fresh fuel and oil at 50:1.<br />11. Fresh coat of enamel over scuffed lower unit (except anodes)<br />I then took it to the lake and fired it up on the trailer. It took a few tries to get it started and warmed up but it pulled off the trailer easily enough. Every time I tried to throttle up on plane, I had to pull the motor back to the transom to even keep the rpm's up. I did manage to get it up on plane once and run it for a few seconds but the engine started bogging (losing RPM's) and fell off step. I remebered reading the sysptoms on this board and tugged it back on the trailer. <br />When got home, I pulled all three carbs and tore them dowm. They soaked all week and I reassembled them tonight.during the week, I charged all three batteries (with deepcycle style charger from sears) and am planning to reinstall the carb tomorrow. <br />I also plan to pull compression numbers.<br />The tch does not seem to work at the moment but neither did any of the other guages. Mice had chewed all of the wiring so I rewired the dash with the exception of the tach. Plan on this once motor runs smooth.

 

[silenscurator]

Re: Newbie Help

Well, when it comes to tuning the motor and figuring out the prop and plane capabilities, it usually requires a tach or rev instrument in place of. WOT RPM determines the blade size and pitch...(specs should be in the manual)...that could cause the problem, could be the trim....if you have auto trim, as i'm sure you do, there may be a sweet spot, but depending on the conditions of the water, that will change. so you may have a "sweet area" that you can play around with. I'm sure people will get back to you on all the technical stuff as i do not own the manual for that particular engine nor do i have access to one...but somebody will.<br /><br />By the way, welcome to Iboats

 

[rodbolt]

Re: Newbie Help

hello<br /> you will find that to take off with that bass boat you will need to trim to full down or nearly so.if that motor is running sweet and the engine is still at or near full trim you will get an excellent view of the sky when you nail the throttle . but on the flip side its incredibly amusing to those of us back at the ramp. cause the next thing you find is that the sudden throttle chop just before planing will allow about a 6" wave of water to wash over the rear casting deck and into the cockpit deck. but on the bright side of that it will test your autobilge switch wiring. before heading to the water for that first ride make sure your tach is working, if the engine has a jackplate you may wish for a water pressure gauge. and by all means test the overheat warning system BEFORE your next post is about the auto shut off system.

 

[G DANE]

Re: Newbie Help

You didnt mention anything about changing water pump impeller which should be done at least every other year, and always when motor sat for a longer period. Old impeller vanes can break of and block cooling systems, making very bad things happen in a snap. If it ran with a 27" pitch on that particular boat you will need possibility to monitor RPM's when turning a 19" pitch or you can accidentaly overrev it.

 

[Rosati]

Re: Newbie Help

While I realize there are issues with buying an old motor, I have addressed the issues with some success. Cleaned carbs have yet to be tested but I hope soon.<br />The main focus of my questions regard the year interchange, the difference between a "looper" and a "crossflow" type engine.

 

[DJ]

Re: Newbie Help

Post a model number and serial number, that will tell which one you have.<br /><br />A "looper" is a loop charged engine. It has to do with the way the fuel/air mixture is drawn into the cylinders. In essence, it uses the exhaust gases to scavange the cylinder and draw in the new fresh charge.<br /><br />The crossflow is exactly as the name implies.