Compression low Evinrude 150XP

[ChevyReb]

Hello to all,<br /><br />I have a 1989 Evinrude 150XP model 150STLCEM.<br />Looking at the back of the motor the bottom starrboard side cylinder is only reading 85lb.s of cranking compression. All other cylinders are between 105 and 115lb.s. This was done with the throttle wide open for several revolutions.<br /><br />When sqirting some oil into the troubled clylinder and running compression check again it comes up close to the others. I am thinking I have bad rings or a scored cylinder.<br /><br />I guess the next thing I should do would be to pull the head off and get the piston to bottom dead center and inspect the cylinder wall right?<br /><br />OK heres where I need some help. I would like to take the engine down and rebuild it if the block is good. I need to know the answers to the following ?'s please.<br /><br />Q1. What special tools will be required? ie... flywheel puller etc to get the engine apart and back together?<br /><br />Q2. What is the best manual(s) available to get that includes engine spec's and tollerences and disasymbly/reasymbly instructions preferably with some decent illistrations? Where do I get one from?<br /><br />Q3.I have rebuilt several auto engines, what are the main differences and "gottcha's" to look out for on a boat motor?<br /><br />Q4. I know it has no cam being a two stroke and the bearings are different. I have also heard that the pistons in this year motor do not like, or were not manufactured for use with lead free fuel, fact or fiction? Should I get all new pistons or can I just get one if one is bad and bore just the one cylinder and put all new rings in?<br /><br />Q5. I also would like to replace the water pump. What other parts should I replace while going through it?<br /><br />Q6. What should it cost to have the block bored if it needs it.<br /><br />Q7. What are some good places to get parts for decent prices.<br /><br />Sorry for the long read, but I want to get as much information ahead of time as possible. Wife will be ready to go out soon so I need to get started fast. <br /><br />Thanks A Lot!!!<br /><br />ChevyReb

 

[rickdb1boat]

Re: Compression low Evinrude 150XP

Decarb the moter and see what you get. Could have a sticking ring.

 

[ChevyReb]

Re: Compression low Evinrude 150XP

Thanks for the reply RB. Would you mind letting me know the best way to go about that please.<br /><br />Thanks,<br /><br />ChevyReb

 

[ChevyReb]

Re: Compression low Evinrude 150XP

Thanks for the reply RB. Would you mind letting me know the best way to go about that please? decarbing that is...<br /><br />Thanks,<br /><br />ChevyReb

 

[DJ]

Re: Compression low Evinrude 150XP

Use the search function on this board and use the search word: decarb<br /><br />HANG ON, you'll get plenty to read.

 

[ChevyReb]

Re: Compression low Evinrude 150XP

Thanks DJ,<br /><br />I thought about doing that after I had posted my reply sorry. I have read several of the hits from the search. One of them said something about leaving the stuff in the engine overnight. <br /><br />I thought the Decarb thing was when you spayed a can of cleaner in the engine while running like cleaning a fuel injected car. How do you leave it in overnight? Spray some in the spark plug hole??? Or is this something different? I just never heard it called decarb before.<br /><br />I think the guy at the shop has done that already though. But a can of cleaner is cheep enough I guess it can't hurt to try again before take more drastic measures.<br /><br />If that does not fix it I will pull the head next.<br /><br />Thanks guys,<br /><br />ChevyReb

 

[DJ]

Re: Compression low Evinrude 150XP

Make sure you use a decarbozing agent. I recommend one from a boat engine dealer (outboard). It doesn't matter which brand.<br /><br />Anyway, spray the stuff in the carb throats while running at just above an idle. Kill the engine by flooding the carb throats with the decarb agent.<br /><br />Let it sit overnight then run it out the next day.<br /><br />Get ready for some serious smoke. <br /><br />Also, be aware that the decarb process is very hard on spark plugs.

 

[Solittle]

Re: Compression low Evinrude 150XP

Reb - One can of decarb won't do it . Some suggest using one can per carb. In addition to the stuff that came up on search the directions are on the can. When you are done take it out for a good WOT run and recheck the compression and post the results back here.<br /><br />The best advice I can give you is to get the OMC Service Manual and Parts Catalog for your motor. There are several publishers of shop manuals but the OMC is the absolute best. Try here:<br /><br /> http://www.theoutboardwizard.bizhosting.com/parts_service_and_owners_manuals.html