Mercury Mark 55E

[jeff-register]

It may need crankcase seals, or mating surfaces leaking making it run lean, and or low compression Do a compression test & post. Have you tested the oil & gearcase? Friction will load a motor. On the top of the cylinderblock it has a test plug for water. Put a barbed fitting for a 1/4″ pee hole to be sure the cooling water is getting to the top cylinder. When running squeeze the primer bulb. Should be soft when running & hard when stopped.

[bbradb]

Everyone responding…. All comments and suggestions will be followed up on. Much appreciated.
1. Yes, gas knob on top of tank fully open.
2. 40 :1 gas mix as we were instructed.

Operations question… Is the pull out knob on top left of motor a choke or what. I read instructions on engine plate that one should flip that up and let it fall until it stays up to prime engine maybe. Does that make sense? PO said that choke was automatic?? There may be a choke button on the throttle/shift control but not sure at this moment. Sounds like I can do alot with motor on boat on trailer? I’m on the lookout for a half a 55 gal drum to make up a stand. Any ideas on that would be appreciated. Gues the problem there is that all controls would need to be pulled from boat or disconnected. Is that true. At what point is it best to pull motor off boat for repairs? You can tell I’m new at this.

[dave-bernard]

ALL repairs can be done on the boat even a full rebuild. If you take the motor off the boat you will put it on a motor stand . which is just a movable transom correct. the choke on the top cowl is only for manual starting the choke for electric starting is on the control box. you should here a click when you push the choke button. 1 914 310 7086.

[bbradb]

Update… Made some progress today. Checked compression and I was satisfied: 130, 125, 130, 125. Ran motor in barrel for a bit. Wondering about water stream from cooling system. As I understand it this is primarily to indicate that the pump is pumping water and that much of the water return is via the center of prop maybe. Is this correct? I took a video to show magnitude of stream but am unable to upload here. Hmmm. How can I describe? I’m an old guy with the typical plumbing issues if you know what I mean guys. I do about the same as the Merc, slow but steady and sure. My son felt it should be much stronger. We are suspicious that cooling could be an issue. I’m suspicious that this area has been worked on not long before we bought engine. The first video I saw of motor running showed no evidence of a water stream. When I talked to PO, he made a point of showing me impeller he had recently removed and replaced. Honestly, I wondered why he did that since he stated early on that motor “was completely overhauled” even if without a manual?? Wouldn’t a new impeller go in along with overhaul?

If I wanted to check impeller and water pump, where would I start? Manual seemed to start with “pull the lower end”.

Also, someone in thread indicated there was a plug high on the block that could be opened to check that water was getting up there? I couldn’t spot that. More clues please. Where is plug and what is purpose. Somewhere I read one could attach a gauge and actually measure water pressure? Is this true?

Thanks for all ideas.
Bruce

[dave-bernard]

call me 1 914 310 7086.

[labrador-guy]

bb, Here is a picture of our M55, (mine and my sons). This one is a ’56 model. I have been told that the teltail gets plugged. You might want to check yours! This picture is at first start and a fast idle. The stream has sense slowed down some but still visible. I also enlarge the opening when the motor was apart. Hope this helps.

dale

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