Evinrude V-4 Crossflow-Surges

[DJ]

Hello Everyone,<br /><br />I took the project boat out again today. I ran into a little problem, that just developed.<br /><br />The engine is a 1983 Evinrude V-4 crossflow 90 hp. (E90ELTCE)<br /><br />The issue is the engine would not reach full (before achieved) rpm of 5400. Top rpm today was 4500. In addition the engine surged while getting up on plane.<br /><br />In my mind, that says fuel starvation.<br /><br />Here is what I did.<br /><br />1. Switched tanks and hoses-same.<br /><br />2. Made sure primer bulb remained hard-it did in both instances. Hitting the primer didn't seem to help.<br /><br />This engine has had both carbs rebuilt-by me.<br /><br />I did notice that the right, from rear, cylinder bank seemed to be running lean. This was determined by examining the spark plugs. Compared to the left bank, the right was noticeably drier.<br /><br />The engine idled fine and ran great up until about 3600 rpm, then the surging started.<br /><br />My question is: how does the fuel/air mixture flow through a crossflow? The manual is of no help. Does one carb. feed one bank of cylinders and the other the other bank?<br /><br />Am I looking at a carb. problem (which one) or a possible reed plate problem? <br /><br />By the way, the only things I have changed since the last outing were the spark plugs (Champion L77J4) and the rectifier.<br /><br />Any ideas?

 

[Joe Reeves]

Re: Evinrude V-4 Crossflow-Surges

DJohns..... I think that the problem here is that your engine according to the model number you listed (E90ELTCE), idicates that you have a 1938 model (grin).... couldn't resist. I know, the "CT" got transposed (1983).<br /><br />The primer bulb shouldn't stay hard unless it is in a vertical position. Normally they lay horizontal, and when running, the fuel drops down in the bulb somewhat, allowing the bulb to be somewhat flexible.<br /><br />The top carb feeds the two top cylinders, bottom carb feeds the two bottom cyls. Port throats feed the port bank, starboard throats feed the starboard banks.<br /><br />The term of "surging" to me means that the engine is gradually increasing and decreasing rpms. I agree with you that this would indicate a fuel problem. This type problem is usually caused by a slightly leaking "O" Ring at one of the fuel connectors.... if they are the OMC type snap on connectors. It could be a air leak anywhere, or a fuel restriction, usually a sticking Anti Siphon valve where the rubber fuel hose attaches to the built in fuel tank.<br /><br />You indicate that the starboard bank appears to be running lean. If the engine had been sitting for quite some time, tilted and leaning towards starboard, that would allow the high speed jets that feed the starboard bank in both carbs to be at the lowest point in the carb. It's rare but it has happened, and it is possible that those two starboard high speed jets (both carbs) are slightly fouled.<br /><br />I assume that you have those Champion L77JC4 s/plugs set at .040. (not .030).

 

[DJ]

Re: Evinrude V-4 Crossflow-Surges

Joe,<br /><br />Thanks. I am going to start looking for air leaks. I never did trust those fuel line to engine connectors. I think it's time to replace one and have another shot at it.<br /><br />Yes, the plugs were set to .040"<br /><br />Thanks again.