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1957 Evinrude 5.5hp won’t go to max rpm underload

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kakon864

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So I finally have my Evinrude 5.5 pumping water and starting good and then I take it out to the lake and it’ll get to max RPM when it is in neutral, but when I lower the throttle and put it in forward it’ll only get to around half of max rpm and was going 4 mph according to my fish finder. I messed with the idle screws a lot, but It couldn’t seem to get up there(except when it was out of gear). Any ideas. It doesn’t seem to be lacking fuel since it was able to get to approximately max while not in gear
 
Never rev a engine past high idle without a load on the prop. Do a cylinder drop test while idleing pull a plug wire and put it back on quickly. The engine should respond the same on both cylinders? With the engine off give it full throttle and look that the throttle butterfly is fully open. It takes alot less fuel to rev up without a load on the prop. How big is the boat? The 5.5 is mot a power plant just a trolling motor.
 
Classic symptom of a motor running on one cylinder.-----It could well be the shock absorber under the water pump is binding.-----Most motors will rev just fine in neutral even on one cylinder !
 
By your description, it is 99% chance it is running on one cylinder. Unless they have already been replaced, it needs new coils. Possibly points/condensers/plugs/wires also. Have you checked compression?
 
I only replace one coil that didn't give any spark because i was being cheap, but ill go ahead and order another coil and see what happens. The boat is a 14ft 1957 crestliner commodore and my trolling motor makes it go almost as fast as with the 5.5...
 
A timing light will also tell you if it is getting spark on both plugs. These little engines are real sensitive to ignition timing and timing is dependent on point gap. On the side of the points plate is two marks about 1/4 inch apart. Connect the timing light to any 12 volt battery and clip the reluctor on a plug wire and start the motor. Shine the light at the two marks and the mark on the flywheel should be inbetween the two marks on the plate. Adjust the point gap for that culinder intil you make that happen. Then do the same for the other cylinder. Adjust engine sync next on the throttle cam attached to the points plate is a mark you want the carb to just begin to open as the mark on the cam passes center of the roller. To adjust sync loosen the two bolts holding the cam on and adjust the cam position to make that happen. You can add a kill button for real easy restarts. With the flywheel off add two wires one to each set of points. If necessary drill a hole in the plate and install a grommet to put the wires through and run them to a kill switch. That should be a one pull start motor are you installing the coils properly? You must pull the plate then pust the plug wire in fully then push the boot up tight. Install the coil and use a straight edge to square the front of the laminate to the machined edge of the boss the coil sits on. Did you install new points and condensers? If not now would be the time and be sure to clean the points with acetone or lawuer thinner as well as your feeler guages a little skin oil will damage new points in no time.
 
kimcrwbr1 said:
A timing light will also tell you if it is getting spark on both plugs. These little engines are real sensitive to ignition timing and timing is dependent on point gap. On the side of the points plate is two marks about 1/4 inch apart. Connect the timing light to any 12 volt battery and clip the reluctor on a plug wire and start the motor. Shine the light at the two marks and the mark on the flywheel should be inbetween the two marks on the plate. Adjust the point gap for that culinder intil you make that happen. Then do the same for the other cylinder. Adjust engine sync next on the throttle cam attached to the points plate is a mark you want the carb to just begin to open as the mark on the cam passes center of the roller. To adjust sync loosen the two bolts holding the cam on and adjust the cam position to make that happen. You can add a kill button for real easy restarts. With the flywheel off add two wires one to each set of points. If necessary drill a hole in the plate and install a grommet to put the wires through and run them to a kill switch. That should be a one pull start motor are you installing the coils properly? You must pull the plate then pust the plug wire in fully then push the boot up tight. Install the coil and use a straight edge to square the front of the laminate to the machined edge of the boss the coil sits on. Did you install new points and condensers? If not now would be the time and be sure to clean the points with acetone or lawuer thinner as well as your feeler guages a little skin oil will damage new points in no time.
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The points looked fine when I gapped them last time, should i really replace them? also I don't got a timing light, What do you recommend gapping them to?
 
The flywheel says .020 and normally work good just try and get them exact as possible. My 4hp was difficult to adjust the carb until i set the points with a timing light. Auto part stores here will let you borrow a timing light just leave a deposit.
 
kimcrwbr1 said:
The flywheel says .020 and normally work good just try and get them exact as possible. My 4hp was difficult to adjust the carb until i set the points with a timing light. Auto part stores here will let you borrow a timing light just leave a deposit.
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OK, also i forgot to mention that I have it on a fuel pump instead of a pressure tank. This is the pump https://www.amazon.com/gp/product/B00S0RX9VC/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 Is that adequate? also can I get away with not buying new points and condensers?
 
Has a compression test been done , yes or no ?----Have you heard of this shock absorber in the lower unit binding , yes or no ?
 
racerone said:
Has a compression test been done , yes or no ?----Have you heard of this shock absorber in the lower unit binding , yes or no ?
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Did a compression test last week after replacing head gasket and it was 75 in both cylinders. I have heard of such a thing as the lower shock absorber binding, but haven’t check mine. Is there an easy way to look at it?
 
Check for spark with a open air spark gap tester you can make one with a small board and a old spark plug wire. Cut the wire and staple a 1/4 inch gap connect one end to engine ground and the other to a plug wire. There must be a brite blue snap?
 
The top wire isn't giving me any spark now, and that is the one with a new coil. Maybe the wire came out of the coil somehow? The bottom one with the old coil is giving me a light spark at 1/4 inch, so I'll have to check the top coil out when I put in the bottom coil.
 
If you did not pull the points plate you did not install the coil properly. Look at how the old coil is sitting on the plate the edge of the coil laminat must be flush with the machined surface the coils are sitting on.
 
Installed the new coil and fixed the other new one ( pulled the plate this time) Runs good, haven't gone to the lake yet to test it yet, but I noticed that the armature plate is way too loose and will vibrate and change the throttle. I put all the screws back in place, so not sure why it's so loose. Got to pull the plate again to check on it. Any ideas why it's so loose?
 
kimcrwbr1 said:
The flywheel says .020 and normally work good just try and get them exact as possible. My 4hp was difficult to adjust the carb until i set the points with a timing light. Auto part stores here will let you borrow a timing light just leave a deposit.
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Cant go wrong by checking with a light
 
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