New water pump/gearbox affecting performance

[Neil]

Gents,<br /><br />I have successfully managed to swap my water pump and lower unit on my Evrinrude 140. Some of you will undoubtedly remember the saga.<br /><br />All works fine and I get a strong stream of water.<br /><br />However, I have some concerns. When I first started the engine there was a loud whining noise. I put this down to the new rubbers on the pump impeller. Also, the engine didn't want to run at idle. It seemed to go slower and slower and then stall.<br /><br />When I took the boat out it still performed OK at high speed, but it had problems at crawl. The engine would just stall.<br /><br />I brought the boat back and ran it in a tank for 10 mins. It ran OK without any hickup and the whining noise decreased.<br /><br />Big question. Is it likely that a water pump couold have so much drag when new that it will affect the idle speed? Maybe I have done something wrong?<br /><br />The other issue to consider is that I replaced my gearbox with a friends. His power unit failed so he gave me the rest to use on my boat. No problems with the gearbox that I can tell with forward/reverse etc.<br /><br />Any help appreciated.<br /><br />NG

 

[G DANE]

Re: New water pump/gearbox affecting performance

Are you sure youdid not drop any little part <br />ind the gap between the drive rod and the housing in the gear box. If you did, f. exa ths old key from the impeller, it would cause lot of friction and a sound. <br /><br />I would check.

 

[petryshyn]

Re: New water pump/gearbox affecting performance

>Pull the spark plugs<br />>install ear-muffs(water supply) <br />>rotate flywheel by hand(in clockwise rotation only). check for binding in nuetral and in gear. <br />>if you feel any binding...loosen all leg mounting bolts 1/8" and again rotate the flywheel. any better? if better...end play or alignment issues<br />> if binding still present, remove leg, rotate driveshaft in clockwise rotation. any binding? if so,disassemble and recheck work.<br />>remove water pump impeller(just slide it up out of housing). any shaft binding now?<br />>if still binding......gear box issues...<br /><br />good luck friend...

 

[Neil]

Re: New water pump/gearbox affecting performance

GmDane, Schematic<br /><br />Good advice. I never thought it could be something I left inside. The old key could be a favourite. I will do a slow dismantle as advised.<br /><br />Let you know.<br /><br />I dont suppose any of you know how to get my tacho working do you. I have no idea where it connects to. <br /><br />NG

 

[petryshyn]

Re: New water pump/gearbox affecting performance

is this a 'new' install or an 'existing' on your tach?

 

[12Footer]

Re: New water pump/gearbox affecting performance

Whining sound may be a vaccum leak. If you lose vaccum,it will run rough and stall at idle. Check around all the fittings from the tank to the carb. Check fuel pump bolts for proper torque. check carb bolts for same.

 

[Neil]

Re: New water pump/gearbox affecting performance

Guys,<br /><br />Checked for bits left inside and all clear. <br /><br />The whining has now decreased to a level where it is barely audible, although I know it sounds different that before.<br /><br />Although it sounds stupid, it did seem as if the new water pump was the cause and the increased friction was to blame. The engine is performing OK although it does often make me wonder if it is going to stall when I go really slow (as if there is still too much friction). The engine doesn't run rough or lumpy so I don't think I have a vacuum problem. Worth checking anyway though.<br /><br />The tach question. It is an existing unit. When I crank the engine the tach does pulse slightly so it is has an electrical connection.. I have a complete set of electrical spares from a spare engine if needed.<br /><br />NG

 

[petryshyn]

Re: New water pump/gearbox affecting performance

Hi NGRIFF1 <br />The tach gets its signal from the charging system.<br /><br />>If the charging system is dead, the tach has no signal to operate. The tach likely gets its signal from the regulator, which is fed from the stator.<br /><br />>stator > a/c voltage > regulator > tach<br /><br />1. check to see if charging system working<br />2. if charging system ok, check to see if tach is getting a good ground, 12volts with key on , and a/c voltage at sensor terminal while running.<br /><br />good luck

 

[Neil]

Re: New water pump/gearbox affecting performance

Schematic,<br /><br />Checked the battery output. Yes it is getting a charge. Not a fantastic amount like on a car (cars usually push 13plus volts on charge) but what I see is a steady increase in voltage up to 13 when it is fully charged. What I mean is, when I crank the engine the voltage goes to about 11, then when the engine runs it steadily increases to 13 over a period of time. From this I assume the charging circuit is OK. And I have no problems in this area either.<br /><br />I have checked the tacho connections. This appears to be good also. Someone suggested a powerpack but I presume this is the same as the regulator pack ?? It has a good ground but no voltage when running. What sort of pulse does the tacho get ?<br /><br />Whilst I have your attention and can tap into your brain, another question or two please. <br /><br />My whine has now decreased in volume although I can still make it out. The boat also seems to perform ok at high speed. What is doesn't like though is running at slow speed. Idle is OK but when I engage gear it sometimes cuts out unless I quickly accelerate. I think it needs some throttle adjustment. Looking at it it seems very complicated with lots of linkages. Is it a simple task to adjust so when I engage slow forward the revs increase to compensate.<br /><br />I have noticed that when I accelerate, the boat takes some time to get onto the plane. I get lots of revs, the bow seems to point higher than normal and eventually drops as the speed picks up. When I changed gearbox I didn't replace the large fin I had above the cavitation plate. Could this have an adverse affect?<br /><br />Thanks for your help<br /><br />NG

 

[johnkc]

Re: New water pump/gearbox affecting performance

NGRIFF1, you say you swapped out lower units ,are the drive shafts the same length , i don't know what year you have but, somewhere in the early ninetys there was a drive shaft length change and if the d.s. is too long it will cause a bind and noise some one with more omc knowledge needs to chime in here.

 

[Rex]

Re: New water pump/gearbox affecting performance

At low speed before did it do this?<br />Have you check your low idle speed jets?<br />Did you turn the lower unit by hand?<br />What is you max. rpm?<br />Did you do a compresion test?<br />Need to know all or the above for<br />everybody to help you out.<br />GOOD LUCK<br />REX A.

 

[DJ]

Re: New water pump/gearbox affecting performance

Did you by any chance put a new O'ring on the drive shaft that goes into the powerhead? If you did, the old one may still be in the powerhead. This will cause a bind on the driveshaft and crankshaft bearings.

 

[Neil]

Re: New water pump/gearbox affecting performance

Great input.<br /><br />Shaft length. As far as I can tell they are identical. Are there markings I can check for sure ?<br /><br />Idle. Yes, but I didn't notice it as much. I don't have tacho so I don't know revs. I haven't done a compression check. When the boat is going it really moves so I don't suspect compression, but I am a novice so I know little about how it should go.<br /><br />I haven't checked jets either. No idea how too. I don't even have a manual, although one is supposidly being shipped.<br /><br />(I don't suppose anyone knows where I can get a adobe online manual).<br /><br />The o ring. I just checked my old shaft. No o ring present. Alarm bell ringing here. Looks like I am dropping the gearbox tomorrow for a looksie. I didn't struggle to get the new shaft in, but it is worth checking. I thought I heard a noise as if something was rubbing inside my flywheel when I was giving the engine a watering yesterday. <br /><br />Still need some help on the tacho please.<br /><br />Let you know if I still need help on the others.<br /><br />Thanks <br /><br />NG

 

[petryshyn]

Re: New water pump/gearbox affecting performance

 

[petryshyn]

Re: New water pump/gearbox affecting performance

Hi NGRIFF1:<br />First off.....I think you may be on to your whine. You say you hear rubbing under the flywheel? Is there any metal filing or metalic dust on or around the engine or flywheel area? Did you remove plugs and rotate engine by hand as previously asked?<br />The output of the charging system sounds questionable and may be related to the above "rubbing" problem. This may warrant pulling the flywheel and having a look.<br /><br />As far as the tach.....<br />First you must identify all wires going to tach. Then you must check the function of each wire.<br /><br />>ground<br />>live with key on only<br />>live with lights on only<br />>a/c volts when engine running<br /><br />Once this is done, it will identify the problem. I'll draw a diagram for you if you wish. <br /><br />What "make" of tach is it?<br /><br />

 

[Neil]

Re: New water pump/gearbox affecting performance

Some feedback on the whine.<br /><br />Yes I had removed the plugs and turned by hand. I couldn't feel or hear anything and I could turn OK.<br /><br />I just split my gearbox. The o ring that fits into the crank housing now has a serated edge. I couldn't see another ring in its place but fragments of what looks like a ring. Cleaned it all out and replaced. I didn't have a new o ring but I will have to get one soon. The serations match the splines at the end of the gear shaft. Looks like either there was another ring still in situ or it didn't locate properly.<br /><br />I didn't run up the engine, I will have to do that some other time soon.<br /><br />No sign of any metal. Is flywheel pulling straight forward? <br /><br />Tach. I will revert after thourough testing.<br /><br />Thanks

 

[RobertR]

Re: New water pump/gearbox affecting performance

would recommend you take the motor to a mechanic and have it checked. There should be no reason for the gearcase to put a load on the motor unless as another suggested it is from a newer model motor. You can have power loss from a number of areas including fuel and electrical. <br /><br />When you bolted on the lower unit did you have to force the unit up with the bolts or did it simply move up freely? The difference between the new style lowers and the older ones is only about 1/4-3/8".<br /><br />The water pump impeller doesn't have enough resistance to cause a drag on a running motor. Something has gone haywire and you need to find it before you cause real engine damage.

 

[DJ]

Re: New water pump/gearbox affecting performance

Glad you looked into the "O" ring. It may be stuck in the crankshaft. It fits into an internal groove in th end of the crank. It is not fun to try and remove the old ring with the powerhead still sitting on top of the exhaust housing. My suggestion is to find something long and metal that you can form a hook on the end. Stick it up the exhaust housing and fish around the bottom of the crank that the driveshaft goes into.<br />If you're lucky you'll pull it out in one piece.

 

[petryshyn]

Re: New water pump/gearbox affecting performance

ditto djohns<br />might want to make an extention for a shop air 'blow nozzle' out of a piece of copper or steel tubing. Make the extention long enough to bottom out in crank. Pull back slightly and blow.<br /><br />good luck!!

 

[DJ]

Re: New water pump/gearbox affecting performance

Ditto schematic. Great idea with the air hose.