Mudboat Posted November 15, 2004 Share Posted November 15, 2004 First of all I would like to say hello to everyone in this forum. I'm new to the forum, but from reading through a few threads before actually registering, I can see that there is a lot of knowledge in here. Hopefully someone can help me with my troubleshooting issues of my engine. 82-84 model 1800cc Subaru engines are the most popular application for South Louisiana mud boats due to their size, weight and power. There are literally hundreds of these boats in my area. The engines are mounted inboard with a shaft through the bottom like most larger boats. A stick rudder steers the boat through the ditch-like runs in the marsh. Some engines are coupled to a 1-1 ratio marine clutch for forward-neutral-reverse, while others are a simple straight drive (start it and go).. Both work great in the marsh. Now for my specific problem... Here is what I know about my engine: Year - ? Size - 1800cc Carb - Carter/Weber TYF-7629S Disty - ? After sitting up for a few months, I took it out for a spin before hunting season to make sure it still runs ok. First thing I noticed was excessive smoke coming from the crankcase vent. I ran a compression check and found 40 psi in one cylinder. I changed the piston and rings. The cylinder wall was fine. Ran a hone through it, wiped it and installed the new one. While I had it in the garage, I decided to clean the carb, change the dist cap, rotor, wires, plugs, air and fuel filters. I put it back in the water and it ran fine through the no wake zone at an idle. when I started to get on it in open water, the engine would run great for about 30 - 45 seconds and then sputter before almost killing. If I let up on the throttle when this happened, it would go back to idle and run fine again. When I would start to get on it again, the same thing would happen. Here is what I checked and done so far: Changed the coil Checked timing - ok Pulled the top off of the carb and checked the float valve. - ok Changed the electric fuel pump I ran it again yesterday and it did the same thing. Frustrated, I went to Roo Builders web site last night and ordered a remanufactured carb. I also suspect that there may be a problem with the pickup coil or vacuum advance.. ?? Don't know.. Does anyone have any thoughts on what I can check next? I'm in a hurry because hunting season opens this coming weekend... Thanks in advance.. Quote Link to comment Share on other sites More sharing options...
86subaru Posted November 15, 2004 Share Posted November 15, 2004 sorry can not help you ,but i would like to see pics of the subaru motors being used as a boat motor ,very interesting Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 15, 2004 Author Share Posted November 15, 2004 I do not have any pictures of the boat. I never thought to take any. They are mostly 16' long, flat bottom, 32" wide bottom w/24" high sides toward the stern. Some have a tunnel drive. All are keel cooled (water circulates through a special set of radiators built into the hull and cooled by the sea water). The seat is mounted over the engine. There is a local manufacturer that custom builds these boats and rigs them according to the customer's specs. A fully rigged boat with an 82-84 model 1800cc engine sells between $11,000 and $14,000 depending on the bells and whistles installed. Some have an engine-mounted hydraulic pump and hydraulic steering. The boat has trememdous power for its size and can run in merely inches of water. Hydrilla and water lillys are no match. Designed for shallow marshes, the top speed is 35-40 mph depending on the weight. Quote Link to comment Share on other sites More sharing options...
Caboobaroo Posted November 15, 2004 Share Posted November 15, 2004 the Carter-Weber engines range from the end of '82 to the beginning of '84 but they were mostly produced in '83. My advice, change the carb and the intake. Those Carter-Webers, granted they CAN be good carbs, are the biggest headache you can have. I had an '83 hatchback that I could never get it to run right with that carb on it. If you do that, then you can swap a Weber 32/36 on there and have more power coming from that motor. Also check the vacuum advance like you mentioned at the end of your post. Age eventually take there toll on that part thus making your motor run like crap. Either use a vacuum pump with gauge to test it or pull the line off of the carb and suck on it with the cap and rotor off. If you see it start to move slowly back while you're sucking on it, you have a bad advance unit. I hope this helps! Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 15, 2004 Author Share Posted November 15, 2004 the Carter-Weber engines range from the end of '82 to the beginning of '84 but they were mostly produced in '83. My advice, change the carb and the intake. Those Carter-Webers, granted they CAN be good carbs, are the biggest headache you can have. I had an '83 hatchback that I could never get it to run right with that carb on it. If you do that, then you can swap a Weber 32/36 on there and have more power coming from that motor. Also check the vacuum advance like you mentioned at the end of your post. Age eventually take there toll on that part thus making your motor run like crap. Either use a vacuum pump with gauge to test it or pull the line off of the carb and suck on it with the cap and rotor off. If you see it start to move slowly back while you're sucking on it, you have a bad advance unit. I hope this helps! Do you have any recommendations or part numbers for the intake and carb you mentioned? Quote Link to comment Share on other sites More sharing options...
Caboobaroo Posted November 15, 2004 Share Posted November 15, 2004 basically you can get all of it from people on the board. You need a intake from an EA81 that had the 2-barrel hitachi on it. Hell you could just run the stock hitachi carb and they're very easy to work on as well. If that doesn't satisfy your hunger for power, then you'll need an adapter for a Weber 32/36 or a Holley 5200 (cheaper version of the Weber). Like I said, ask in the Marketplace on this board for these parts and people will be able to help you out. It would probably be cheaper then a yard, sometimes not. Just gotta ask:D Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 15, 2004 Author Share Posted November 15, 2004 Thanks a bunch.... I'm not really hungry for power since the power is fine for my application. I'm really just hungry to get it running good... Quote Link to comment Share on other sites More sharing options...
Will Smith Posted November 15, 2004 Share Posted November 15, 2004 sounds like it's starvin for fuel. Change the filter? Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 15, 2004 Author Share Posted November 15, 2004 Yes, I changed the in-line filter as well as cleaned the screen on the pickup tube in the fuel tank (a regular 6-gallon plastic boat tank). I also made sure that the tank is properly vented. Quote Link to comment Share on other sites More sharing options...
oddcomp Posted November 15, 2004 Share Posted November 15, 2004 actualy i would think its gettign too much fuel myself check the float setting in the carb and the fuel pump psi or as always .. hehe switch over to do it yerself injection Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 15, 2004 Author Share Posted November 15, 2004 Thanks. Too much fuel is something I never considered. Being the engine is situated at about 15 degrees in the boat, I guess it's possible that the float bowl level is higher than it should be. I'll adjust the float a bit and try it again. Fuel pressure at the carb inlet is 5 psi. One other thing. All of the vacuum ports on the carb and intake are plugged off with the exception of the hose to the distributer vacuum. Is there anything wrong with having everything plugged? It's been like that since I've had it and never had a problem. Quote Link to comment Share on other sites More sharing options...
Snowman Posted November 15, 2004 Share Posted November 15, 2004 I like where oddcomp is going with this. What's the psi for the fuel pump that you are running? I don't know what pressure the Carter-Weber carb requires, but the Hitachi that the subarus run needs relatively low pressure around 3. If the pressure is too high, it's quite possible that too much fuel is being dumped in. Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 15, 2004 Author Share Posted November 15, 2004 The fuel pump is an off the shelf Purolator rated at 4-7 psi. It maintains about 5 psi when I checked it after installing. The one I took off was pumping about 3 psi, but I didn't notice any difference between the two. Quote Link to comment Share on other sites More sharing options...
Petersubaru Posted November 15, 2004 Share Posted November 15, 2004 Hopefully the new carb will take care of the problem along with a new fuel filter and good working fuel pump and a "level" or close enough operating fuel bowl...after that, try pulling the plugs out and see if they are a light tan color...and if they are not, then at this point check for a mis-firing module in the distr.(easy to do if you can change the dist. with another one)-the vac-advance may be shot, but I doubt if it would be the cause for this much power loss...this could be also a problem with a bad valve or two....I have seen people chase all-kinds of problems first without checking the compression and doing a leak down test....if a spark plug looks dark compared to the others, it could be a faulty valve,(hope not).. but first check(better replace) the ignition side of things...wires,rotor ,cap ...when checking the timing,hopefully you set it on the BTDC..and not on the ATDC..some people get confused on this part... the list can go on but I am stopping here....Good luck Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 15, 2004 Author Share Posted November 15, 2004 Already have new cap, rotor, wires and plugs. A level float bowl is not an option because of how it is mounted in the boat (slanted with shaft through the bottom), but there are hundreds of boats with engines like this in my area, and no one else seems to have problems. You have me confused on the timing check. How can you tell where BTDC is in relation to ATDC? I hooked up the timing light to the #1 plug and lined up the mark with the little hole... Compression was checked 1st, that was when I noticed the bad rings in one cylinder (40 psi). The rest were fine. Compression is good in all 4 now. Like I mentioned in my original post, it runs great for a little under a minute before it sputters out and nearly kills. I naturally assume it's either a fuel or ignition related problem. I'm working through it from cheapest to most expensive. Right now everything is new except for the carb and the distributor. ????? Quote Link to comment Share on other sites More sharing options...
Petersubaru Posted November 15, 2004 Share Posted November 15, 2004 on my two subarus. the timing marks on the flywheel are marked A or B on either side of the big "0" (TDC)...offical setting of 8deg. BTDC ...I am curious as to what the plugs look like...keep use posted when you find the problem Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 15, 2004 Author Share Posted November 15, 2004 I never noticed an A or B. I have it lined up with the big "O" on the flywheel. Hmmmm... Maybe I'll try wiping it or something... (Ok, so I don't know much about soobs, but I'm learning more with each reply). You guys are great. I just got off the phone with the guy that builds and rigs mudboats with Subaru engines. He tells me he has 40 something used engines in stock plus piles of parts. He does not recommend the Carter carb in a boat because they are too hard to get set right with the engine at an angle. Looks like my plans to replace the Carter have changed. Anyway, he said he has an intake for a hitachi carb and also has a used carb that can be rebuilt for about $100 for both. He also carries the gaskets. Looks like I'll be changing over to the Hitachi tomorrow evening. I'll pull the plugs this evening and let you know what they look like. They have about 1 to 1-1/2 hour run time on them right now. Quote Link to comment Share on other sites More sharing options...
Nug Posted November 16, 2004 Share Posted November 16, 2004 As soon as you said the engine was at an angle, I knew it was the carter's fault. To be real cheap about it, you could adjust the float level so more fuel enters the float bowl, but that risks having the needle never seating, and fuel running over into the intake with the engine off. You could maybe make a wedge-shaped adapter to sit on top of the intake to get the carb level again. BTW the weber 32/36 really has no problem with this. Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 16, 2004 Author Share Posted November 16, 2004 You could maybe make a wedge-shaped adapter to sit on top of the intake to get the carb level again. BTW the weber 32/36 really has no problem with this. Now that is another good idea that would have never crossed my mind. I have some 1/2" aluminum plate that would work nicely and access to a machine shop. Maybe I'll make the wedge and keep the carter and intake as a spare to try in the future. I've already picked up the new intake and Hitachi, so I'm going with it starting this evening.. Quote Link to comment Share on other sites More sharing options...
Snowman Posted November 17, 2004 Share Posted November 17, 2004 I think you'll be happy with the Hitachi carb. Everybody rags on them, but all the problems are created by the fact that they are dealing with a 20 year old carb that likely hasn't been rebuilt. The stock Hitachi is the best compromise between power, fuel economy, and smooth running. When I still had mine on my wagon, I once went on a 500 mile round trip doing 85-90 all the way except on the long pulls over the mountain pass we were in, and got 18 miles per gallon. Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 17, 2004 Author Share Posted November 17, 2004 Well, the intake was swapped out this evening and the carb looks in great shape. I still bought a rebuild kit from NAPA and my mechanic is going through it tonight. I will have to re-route the throttle cable and install a manual choke cable since the Carter was an auto-choke. The Hitachi is manual. No biggie though. That's life when dealing with a car engine in a boat.... The new intake is a whole lot cleaner and less cluttered than the intake for the carter. I think this was a good move. Thanks for the suggestions and ideas. I will let you know how it runs on Thursday.... If anyone is interested, Boats by Kirk in Des Allemands Louisiana has stacks of low milage EA-81 and 82 engines. He sells them for $700... I think he paid $500 each from a dealer overseas.... I'm thinking about buying a spare just to keep on hand. Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 18, 2004 Author Share Posted November 18, 2004 Rebuilt carb installed. It took me all evening (6hrs) to cut out and mill the throttle and choke cable brackets, but everything is in place. Hooked up the fuel line, vacuum hoses and filled the reservoir with anti-freeze. Turned the key and it came back to life immediately!! The Hitachi carb seems to be super responsive as compared to the Carter. I'll know more tomorrow when I launch the beast and take it out for a test run. All indications are that I should get 3-5 mph faster, but speed is not a factor in a mud boat. It's power that counts.. I'll post the results after the test run... Again, thanks for the tips and info on this problem. If it is indeed solved, the total for the fix will be under $100 and roughly 10 hours labor. Of course most of the labor went in to fabricating custom brackets to accomodate the new carb.. Quote Link to comment Share on other sites More sharing options...
Nug Posted November 18, 2004 Share Posted November 18, 2004 Excellent. I hope it works out like you hoped it would. Quote Link to comment Share on other sites More sharing options...
Petersubaru Posted November 18, 2004 Share Posted November 18, 2004 let us know what happens Quote Link to comment Share on other sites More sharing options...
Mudboat Posted November 18, 2004 Author Share Posted November 18, 2004 Ok... I set everything today, cranked it up and did a quick timing check. Launched the boat and starting running. Boat started sputtering like it was running on 3 cyls. Black smoke from exhaust. I pulled all 4 plugs and they were black and sooty. I cleaned them, re-installed and cranked it up. It ran fine for a few minutes then it started doing the same thing. I pulled a plug back out and it was getting black and sooty again. I took a wild guess at vacuum hoses when I installed them, but there is basically a hose from the manifold that tees off. One to the vacuum advance and one to the carb. Everything else is plugged. ????? Can anyone tell me what may be happening now? Quote Link to comment Share on other sites More sharing options...
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